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Biomedical subjects

M Yamagata

Publications and source records attributed to M Yamagata.

At least 163 records · Page 9Linked to original sources
PubMed1987

The economic benefit of treating subclinical Streptococcus agalactiae mastitis in lactating cows.

The economic benefits of treating lactating cows for Streptococcus agalactiae mastitis were studied at a large (689 milking cows) central California dairy. Postcure milk production of case cows (infected, treated, and cured) was compared with production of paired control cows (uninfected) and was matched for yield, days in milk, days in gestation, and parity. A simulation was used to plot expected lactation curves for mastitic cows (infected, not treated) with characteristics similar to those of each control cow, and these curves were compared with actual case-cow lactation curves. The difference in actual and expected production was used to calculate net economic benefits of treatment. Comparison of expected with actual production indicated a net benefit from treatment of $396/cow for cows treated in early lactation and $237 for cows treated in midlactation, but a net loss of $55 for cows treated in late lactation. Lactation number did not have a significant impact on economic benefits of treatment. In contrast to other studies indicating no economic benefit from treating mastitis during lactation, this study's positive results may have been attributable to the high cure rate (98%) and the subclinical form of mastitis being treated. Streptococcus agalactiae mastitis treatment during early and midlactation would appear to be an economically justifiable option for dairy managers.

Animals↗
PubMed1987

A monoclonal antibody that specifically recognizes a glucuronic acid 2-sulfate-containing determinant in intact chondroitin sulfate chain.

Monoclonal antibodies produced against chick embryo limb bud proteoglycan (PG-M) were selected for their ability to recognize determinants on intact chondroitin sulfate chains. One of these monoclonal antibodies (IgM; designated MO-225) reacts with PG-M, chick embryo cartilage proteoglycans (PG-H, PG-Lb, and PG-Lt), and bovine nasal cartilage proteoglycan, but not with Swarm rat chondrosarcoma proteoglycan. The reactivity of PG-H to MO-225 is not affected by keratanase digestion but is completely abolished after chondroitinase digestion. Competitive binding analyses with various glycosaminoglycan samples indicate that the determinant recognized by MO-225 resides in a D-glucuronic acid 2-sulfate(beta 1----3)N-acetylgalactosamine 6-sulfate disaccharide unit (D-unit) common to antigenic chondroitin sulfates. A tetrasaccharide trisulfate containing D-unit at the reducing end is the smallest chondroitin sulfate fragment that can inhibit the binding of the antibody to PG-H. Decreasing the size of a D-unit-rich chondroitin sulfate by hyaluronidase digestion results in progressive reduction in its inhibitory activity. The results suggest that the epitope has a requirement for a long stretch of a disaccharide-repeating structure for a better fit to the antibody.

Animals↗
PubMed1987

Fixed-head and bipolar hip endoprostheses. A retrospective clinical and roentgenographic study.

A retrospective review of 1,001 hip hemiarthroplasties was performed. The prosthetic designs were grouped into fixed-head types (682 cases) and bipolar types (319 cases) for comparison. The main indications for operation were femoral neck fracture and avascular necrosis of the femoral head. Clinical and roentgenographic data for different follow-up periods were compared between prosthetic types, using multivariate analysis. Roentgenographic loosening of the femoral component was noted in 25.4% of cases but was significantly higher (P less than .05) in the bipolar groups for a follow-up period less than 2 years, regardless of the method of fixation. The acetabular erosion rate was significantly higher (P less than .05) in the fixed head group, but this finding was related to length of follow-up period, bone porosity, and prosthesis/acetabulum fit. The reoperation rate, including revision to total hip arthroplasty, was higher in the fixed-head group (12.5%) than the bipolar group (7.2%). Based on Kaplan-Meier survivorship analysis, 13.7% of the bipolar and 22.9% of the fixed-head hip endoprostheses are expected to be reoperated 8 years after initial implantation. Cement fixation of the femoral component led to a higher prosthesis survival rate, regardless of type. Both prosthetic types are useful in hip surgery, but the bipolar type appears to be indicated in younger and more active patients, whereas the fixed-head design is more suitable for older patients with femoral neck fractures.

Acetabulum↗
PubMed1986

A large chondroitin sulfate proteoglycan (PG-M) synthesized before chondrogenesis in the limb bud of chick embryo.

Extraction of stage 22-23 chick embryo limb buds that had been metabolically labeled with [35S]sulfate yielded heparan sulfate proteoglycan, small chondroitin sulfate proteoglycan, and large chondroitin sulfate proteoglycan (designated PG-M). PG-M constituted over 60% of the total macromolecular [35S]sulfates. It was larger in hydrodynamic size, richer in protein, and contained fewer chondroitin sulfate chains as compared to the predominant proteoglycan (PG-H, Mr congruent to 1.5 X 10(6)) of chick embryo cartilage. The chondroitin sulfate chains were notable for their large size (Mr greater than or equal to 60,000) and high content of nonsulfated chondroitin units (about 20% of the total hexosamine). Hexosamine-containing chains corresponding in size to N-linked and O-linked oligosaccharides were also present. The core protein was rich in serine, glutamic acid (glutamine), and glycine which together comprised about 38% of the total amino acids. Following chondroitinase AC II (or ABC) digestion, core molecules were obtained which migrated on sodium dodecyl sulfate gel electrophoresis as a doublet of bands with approximately Mr = 550,000 (major) and 500,000, respectively. The Mr = 550,000 core glycoprotein was structurally different from the core glycoprotein (Mr congruent to 400,000) of PG-H, as ascertained by tryptic peptide mapping and immunochemical criteria. Immunofluorescent localization of PG-M showed that the intensity of PG-M staining progressively became higher in the core mesenchyme region than in the peripheral loose mesenchyme, closely following the condensation of mesenchymal cells. Since the cell condensation process has been shown to begin with the increase of fibronectin and type I collagen concentration, the similar change in PG-M distribution suggests that PG-M plays an important role in the cell condensation process by means of its interaction with fibronectin and type I collagen.

Animals↗
PubMed1986

Chondroitin sulfate proteoglycan (PG-M-like proteoglycan) is involved in the binding of hyaluronic acid to cellular fibronectin.

Preparations of cellular fibronectin from chick embryonic fibroblasts have previously been shown to have hyaluronate-binding activity. However, gel filtration and CsCl isopycnic centrifugation of fibronectin preparations showed that the binding activity was associated with molecules with a density and a molecular weight higher than those of fibronectin. An immunoprecipitation assay using antibodies to the chondroitin sulfate proteoglycan (PG-M) from the mesenchyme of chick embryo limb bud showed that the hyaluronate-binding activity of fibronectin preparations was precipitable with this antibody. The immunoprecipitation analyses also showed that fibronectin preparations as well as conditioned culture medium and extracts of chick embryonic fibroblasts contained a chondroitin sulfate proteoglycan, the protein-enriched core molecules from which were identical to those from PG-M with respect to electrophoretic mobility and immunological reactivity. This proteoglycan was purified from conditioned culture medium and extracts of fibroblasts by dissociative CsCl isopycnic centrifugation. The proteoglycans from medium or extracts gave core derivatives with electrophoretic mobility identical to those from PG-M, and they had equal hyaluronate-binding activities. These results, taken together, suggest that most, if not all, of the hyaluronate-binding activity in preparations of chick cellular fibronectin is due to a proteoglycan identical to PG-M. This proteoglycan was also found to bind directly to fibronectin and to type I collagen, but not to laminin or type IV collagen. It is possible that the fibroblast proteoglycan mediates interactions between hyaluronate, fibronectin, and type I collagen, thereby participating in formation of the pericellular matrix of fibroblasts.

Animals↗
PubMed1984

Biomechanical study of posterior spinal instrumentations for scoliosis.

The purpose of this study was to quantitatively evaluate the stability of various posterior spinal instrumentations for scoliosis. At first, several kinds of rod systems were tested under various conditions. Furthermore, six types of instrumentations were applied to the scoliosis-simulation models, followed by vertical compression, three-point bending and torsional tests. The Chiba rod was found to be twice as strong as the original Harrington rod in terms of maximum force. The transverse bar and the stable hooks provided great stability to the rod systems. In the vertical compression test, segmental wiring showed very good stability. Luque L-rod instrumentation, however, was less stiff than Harrington wiring. In the three-point bending test, only segmental spinal instrumentations showed good stability. Harrington-Luque instrumentation and Luque L-rod instrumentation were both four times as stiff as a simple Harrington instrumentation in the torsional load. Harrington instrumentation did not show enough resistance against a rotational load. From the biomechanical viewpoints, Harrington-Luque instrumentation was considered to be the most stable in all three loading conditions.

Biomechanical Phenomena↗
PubMed1975

IgA glomerulonephritis in Japan.

A clinicopathological study was done on 85 Japanese patients with IgA glomerulonephritis. Of patients with glomerulonephritis whose clinical course is of slow progression, the presence of IgA glomerulonephritis was demonstrated immunohistologically. The majority of such patients presented with a mild degree of proteinuria and/or persistent microscopic hematuria. In 15% of the patients, recurrent gross hematuria was noted. These findings suggest that immunohistological study is important in dealing with adult patients with so-called idiopathic renal hematuria. Light-microscopic findings of IgA glomerulonephritis were divided into 4 groups. In 56% of the patients, diffuse stalk thickening of the mesangium was noted and in one third of them, small crescent formations were present. In 22% of the patients, focal segmental proliferation was noted. Diffuse mesangial deposition of IgA noted by immunofluorescence was considered to correspond to the characteristic nodular deposition detected by light microscopy and to the relatively large globular hemispheric deposits detected by electron microscopy.

Female↗