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Biomedical subjects

K Ogata

Publications and source records attributed to K Ogata.

At least 451 records · Page 25Linked to original sources
PubMed1984

A dynamic canine model of experimental hip dysplasia. Gross and histological pathology, and the effect of position of immobilization on capital femoral epiphyseal blood flow.

We produced a dynamic model of experimental hip dysplasia in growing puppies by cast immobilization of a single hind leg with the knee in extension. Serial roentgenographic studies demonstrated a progressive acetabular dysplasia with subluxation and eventually dislocation of the femoral head. A consistent finding in the dysplastic hip was significant hypertrophy of the ligamentum capitum femoris, both in length and in cross-sectional area. Quantitative studies of blood flow in the femoral head by the hydrogen-washout technique in normal and dysplastic hips demonstrated a significant decrease in blood flow to the dysplastic femoral heads. The dysplastic hips were then placed in various positions of immobilization and blood-flow determinations were repeated. The position of forced abduction significantly reduced circulation in the femoral head, whereas immobilization in flexion consistently resulted in the highest rate of blood flow in the femoral head. These experimental data indicate the potential ischemic hazards of immobilization in the forced abducted position in the treatment of congenital dislocation of the hip. Progressive degenerative changes developed in the articular cartilage of the dislocated joint, with severe reduction of safranin-O staining, fibrocartilaginous metaplasia, and hypocellularity. The degenerative changes in the acetabular cartilage were more severe than those in the femoral head. These findings further emphasize the importance of reducing the dislocated hip at the earliest opportunity in order to prevent irreversible degenerative changes.

Animals↗
PubMed1984

Pityrosporum infection in an infant with lesions resembling erythema annulare centrifugum.

Erythematous, scaling patches over the face, torso, and extremities developed in a 2-month-old female infant. The facial lesions enlarged and became confluent, while the torso and leg lesions enlarged and assumed an annular configuration. Spores of Pityrosporum ovale and Pityrosporum orbiculare were found in large numbers in potassium hydroxide preparations from these lesions, a finding confirmed by culture. Clotrimazole ointment was applied, and the lesions resolved within one week, leaving depigmentation. The findings in this case and those of erythema gyratum atrophicans transiens neonatale resembled each other except for the demonstration of Pityrosporum spores. We assume that the disorder in our patient may represent superficial gyrate erythema (erythema annulare centrifugum) induced by Pityrosporum spores.

Administration, Topical↗
PubMed1984

Interlocking wedge osteotomy of the proximal tibia for gonarthrosis.

Modification of the lateral closing wedge osteotomy of the proximal tibia is described for gonarthrosis associated with varus deformities. In this procedure, the anterior and posterior cortices are left attached to the distal and proximal fragments respectively when the bone wedge is removed. The defect is closed by applying valgus stress and medial rotation to the distal fragment so that the tibial tubercle advances anteriorly and the posterior cortex of the proximal fragment overrides the distal fragment. Contact area and stability at the osteotomy site are increased by an interlocking effect of the cortices and the stress under the patella is reduced by anterior advancement of the tibial tubercle. Satisfactory results have been obtained in 36 cases followed for one to three years with few complications.

Female↗
PubMed1983

Detection of toxoplasma membrane antigens transferred from SDS-polyacrylamide gel to nitrocellulose with monoclonal antibody and avidin-biotin, peroxidase anti-peroxidase and immunoperoxidase methods.

Toxoplasma (Tp) membrane antigens separated by discontinuous SDS-polyacrylamide gel electrophoresis were electrophoretically transferred to nitrocellulose and detected with avidin-biotin (AB), peroxidase anti-peroxidase complex (PAP) or indirect immunoperoxidase (IIP) methods. In the AB method, the nitrocellulose was treated with biotinylated monoclonal antibodies and avidin-labeled peroxidase. In the PAP method, it was treated with monoclonal antibody, rabbit anti-mouse IgG antibody, goat anti-rabbit IgG antibody and PAP. Of the two, the AB method was the more sensitive and specific for Tp membrane antigen. The PAP method was less sensitive, but did not require chemical manipulation of the antibodies and was convenient and useful for analyzing Tp membrane antigens. The IIP method was more convenient, but had a lower sensitivity than the other methods.

Animals↗
PubMed1983

Isolation and nucleotide sequence of a partial cDNA clone for bovine opsin.

Bovine cDNAs were cloned by using a mixture of 18-base-long synthetic deoxyribonucleotides as a hybridization probe. The longest cDNA clone (pBO-1) contained an 811-bp insert that included the 434 bp of the coding region corresponding to the C-terminal 144 amino acid residues of opsin peptide and the 377 bp of the 3'-untranslated region. The size of opsin mRNA was determined as 23 S by Northern blot hybridization. Bovine liver DNA gave rise to a single band of 2.8 kb, 1.1 kb and 7.9 kb each with Eco RI, Hind III and Bam HI, respectively, by Southern blot hybridization with pBO-1 as probe. Therefore, bovine opsin gene may occur once per haploid genome.

Amino Acid Sequence↗
PubMed1983

Ribosomal proteins cross-linked to 28-S and 18-S rRNA separated by sedimentation after ultraviolet irradiation of rat-liver ribosomes.

Rat liver 80-S ribosomes, irradiated with 254 nm ultraviolet light for 15-60 min (0.63-2.5 X 10(5) quanta/ribosome), were treated with sodium dodecyl sulfate; 18-S and 28-S RNA fractions were isolated by sucrose density-gradient centrifugation. The protein moieties of the 18-S and 28-S rRNA fractions were labeled with 125I. After digestion of the rRNA fractions with RNase A and T1, the cross-linked proteins were analyzed by two-dimensional acrylamide gel electrophoresis and then autoradiography. Cross-linked proteins were examined further by dodecyl sulfate/acrylamide gel electrophoresis of individual radioactive spots of proteins and their proteolytic peptides on two-dimensional gels. The results showed that S2 and S15 were cross-linked to 18-S rRNA, and L5, L6 and L8 to 28-S rRNA. Similar results were obtained when isolated 40-S or 60-S subunits were irradiated.

Animals↗
PubMed1983

Isolation of Ia positive human leukocytes by a direct rosette assay.

A direct rosette assay (DRA) using ox erythrocytes coated with monoclonal antibody (AF-10) to human Ia-like antigen (OE-anti-Ia) is a rapid and convenient method for detection and isolation of Ia-like antigen-bearing cells. Various cell lines and peripheral blood lymphocytes were tested by DRA. Cell lines expressing Ia-like antigen formed rosettes, while cell lines lacking Ia-like antigen did not. In a highly purified T cell fraction, a small number of T cells formed rosettes; but in a Con A-stimulated T cell fraction, about 40% of the cells formed rosettes. The majority of purified B cells and monocytes formed rosettes. Rosette-forming and non-rosette-forming mononuclear cells could be separated by centrifugation on Ficoll-Urografin. Rosette-forming cells reacted positively by indirect immunofluorescence (IIF), while non-rosette-forming cells reacted negatively. The results obtained by DRA were consistent with those obtained by IIF with OKIa*1 and AF-10. DRA is thus suitable not only for detection of Ia-like antigen-bearing cells, but also for separation of Ia-like antigen-positive (Ia+) and -negative (Ia-) cells.

Animals↗
PubMed1983

Posterior cruciate reconstruction using iliotibial band. Preliminary report of a new procedure.

In the last 3 years, 11 patients with posterior cruciate injury were treated with the reconstructive procedure utilizing the iliotibial band. The operative technique was found to be easy and simple compared with other methods. Strong reconstruction could be accomplished even in the cases of old injury of more than two years. All 5 patients followed for more than a year considered that the knee that had been reconstructed with the iliotibial band was improved compared with its preoperative status.

Adolescent↗
PubMed1983

Protein components of rat lens and their age-related changes observed with two-dimensional polyacrylamide gel electrophoresis.

The protein components of rat lens crystallins were analyzed by two-dimensional urea-sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The following age-related changes were observed. (i) In alpha-crystallin, one or two spots at the anodic sides of alpha A2 and alpha B2 spots were observed in the lens cortex after the 8 months. beta-Crystallin, consisting of seven components designated as beta-1 to beta-7 components in the case of 1.5-month-old rats, showed marked changes during ageing. Component beta-3 was not detectable in neonatal lens. Component beta-5' located at the cathodic side of component beta-5 was observed in the lens older than 8 months. Components at the anodic sides of beta-4, beta-6 and beta-7 spots were detected in 8-month and especially 19- and 47-month-old lenses. The amount of gamma-crystallin decreased in dependence on age. (ii) The electrophoretogram of the nucleus of 8-month-old lens showed additional spots in the area with the lower molecular weight than alpha A2. gamma-Crystallin was accumulated in the nucleus. The electrophoretogram of gamma-crystallin of the 8-month-old nucleus was more similar to that of 19-month-old lens cortex than that of neonatal lens or young lens cortex.

Aging↗
PubMed1983

The blood supply of the tendon with a paratenon. An experimental study using hydrogen washout technique.

The blood supply to the central third of the Achilles tendon was studied in adult rabbits using the hydrogen washout technique before and after soft tissue dissection including paratenon. The soft tissue dissection caused a decrease of the blood flow rate in the Achilles tendon by approximately 35 per cent. These results may indicate that the central third of the tendon with a paratenon receives its blood supply from the extrinsic vascular system by approximately 35 per cent and from the intrinsic vascular system by approximately 65 per cent.

Achilles Tendon↗
PubMed1983

Effects of low dose actinomycin D treatment in vivo on the biosynthesis of ribosomal proteins in rat liver.

The long-term effects (up to 12 h) of low dose in vivo actinomycin D treatment, which selectively inhibits rRNA synthesis, on the activity of rat liver for the synthesis of ribosomal proteins relative to that for the synthesis of total protein were investigated. The effects of actinomycin D treatment in vivo and in vitro on the template activity of poly(A)-containing mRNA of rat liver for ribosomal proteins were examined by using a wheat germ cell-free system. The following results were obtained. 1. The activity of rat liver for synthesizing total protein observed in vivo and in vitro was inhibited by actinomycin D treatment even at a small dose. 2. A double-labeling technique using [3H] and [14C]leucine in vivo showed that the rate of synthesis of the ribosomal protein fraction relative to that of total protein in actinomycin-treated rat liver (6 + 6 h) was 1.45 times higher than that in the control rat. 3. By using a wheat germ cell-free system, it was shown that the template activity of poly(A)-containing mRNA for the synthesis of total protein was increased slightly by actinomycin D treatment in vivo. Furthermore, the template activity for the ribosomal protein fraction relative to that for total protein was increased. This increase was observed in most of the ribosomal proteins separated on two-dimensional acrylamide gel electrophoresis, although the extents of increase were different among individual ribosomal proteins examined. On the other hand, the selective increase of the template activity for the ribosomal protein fraction was not observed when poly(A)-containing mRNA was incubated with actinomycin D in vitro, although the template activity for total protein was increased slightly.

Animals↗
PubMed1983

Binding of actinomycin D to mRNA in vivo and in vitro.

1. When rats received an intraperitoneal injection of [3H]actinomycin D, it bound to the RNA moiety of free and bound polysomes of rat liver. The labeling increased gradually up to 6 h or 6 + 6 h. The poly(A)-containing mRNA showed definite radioactivity and its specific activity was higher than that of rRNA, although the total radioactivity of rRNA was markedly higher than that of poly(A)-containing mRNAs. 2. An equilibrium dialysis method using rabbit globin mRNA showed that the binding constant of actinomycin D to globin mRNA was 0.056 x 10(6) M-1, and globin mRNA had 2 binding sites per mol for actinomycin D. 3. From the results of the present experiments and those described in the preceding paper, it is suggested that one of the mechanisms by which actinomycin D treatment in vivo and in vitro stimulates the template activity of mRNA may be binding to mRNA, which alters the conformation of mRNA.

Animals↗