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Biomedical subjects

Susan Smith

Publications and source records attributed to Susan Smith.

31 records · Page 2Linked to original sources
PubMed2002

Perlecan, the multidomain HS-proteoglycan of basement membranes, is a prominent pericellular component of ovine hypertrophic vertebral growth plate and cartilaginous endplate chondrocytes.

The aim of this study was to immunolocalise perlecan in ovine vertebral growth plate (VGP) and cartilaginous endplate (CEP) cartilages using a monoclonal antibody (MAb A76) directed to a core protein epitope in perlecan domain-I, and to compare and contrast its localisation patterns with known cartilage matrix components. Perlecan was a prominent pericellular component of mature hypertrophic chondrocytes in the VGP and CEP in newborn 2- to 5-day-old sheep. Type I, II, VI and X collagen, chondroitin-4 and 6-sulphate, 7-D-4 chondroitin sulphate isomer proteoglycan epitope, keratan sulphate, aggrecan core protein, hyaluronan (HA) and hyaluronan binding proteins (HABPs) each had distinct localisation patterns in the VGP and CEP. Type X collagen was a prominent component of the VGP but was undetectable in the CEP. Aggrecan was strongly localised extracellularly throughout the VGP and CEP but increased cell-associated staining was also evident. In contrast to the aforementioned matrix components, HA, HABPs and perlecan were localised strongly to the pericellular matrices of the hypertrophic VGP and CEP chondrocytes apparently indicating an important role for these components in terminal chondrocyte differentiation.

Animals↗
PubMed2002

Spatial and temporal localization of transforming growth factor-beta, fibroblast growth factor-2, and osteonectin, and identification of cells expressing alpha-smooth muscle actin in the injured anulus fibrosus: implications for extracellular matrix repair.

STUDY DESIGN: The spatial and temporal localization of fibroblast growth factor-2, transforming growth factor-beta, osteonectin, and alpha-smooth muscle cell actin in the injured anulus fibrosus was investigated. OBJECTIVE: To assess the involvement of fibroblast growth factor-2, transforming growth factor-beta, osteonectin, and alpha-smooth muscle cell actin in anulus fibrosus repair. SUMMARY OF BACKGROUND DATA: Fibroblast growth factor-2 and transforming growth factor-beta have been localized to disc herniation tissue, and alpha-smooth muscle cell actin has been identified in a number of mesenchymal cell types, but their roles have not been evaluated in repair processes in the experimentally injured anulus fibrosus. METHODS: For this study, 32 two adult merinos received a 4-mm deep standard annular incision in their L1L2 and L3L4 discs (lesion group). A similar number of sham-surgery animals served as control subjects. Osteonectin, fibroblast growth factor-2, transforming growth factor-beta, and alpha-smooth muscle cell actin were immunolocalized in sagittal disc sections 3, 6, 12, and 26 months after the operation. Selected specimens also were stained with hematoxylin and eosin, Masson-trichrome, toluidine blue, and picrosirius red. RESULTS: Early focal depletion of proteoglycan was evident in the anulus fibrosus and reorganization of outer annular lamellas 3 to 6 months after the operation. Blood vessel ingrowth and fibroblast infiltration from the outer anulus fibrosus along the plane of the annular defect were maximal 12 months after the operation. Focal upregulation in alpha-smooth muscle cell actin expression was evident with maximal staining in the 12-month lesion samples near infiltrating blood vessels at the lesion site, and also in cells well away from these vessels. Some of the anulus fibrosus cells of the sham sections also stained positively for alpha-smooth muscle cell actin, but this staining was significantly less than in the lesion samples. Staining for fibroblast growth factor-2, transforming growth factor-beta, and osteonectin was strongly localized to blood vessels and cells in the vicinity of the annular lesion. It was maximal 12 months after the operation and diminished by 26 months after the operation. Osteonectin expression also was significantly elevated in outer anulus fibrosus cells distant from the lesion site and its associated blood vessels. In the sham discs, immunoreactivity to fibroblast growth factor-2, transforming growth factor-beta, osteonectin, and alpha-smooth muscle cell actin was confined to sparsely distributed cells in the anulus fibrosus. No matrix staining was observed. CONCLUSIONS: Immunoreactivity for the noted agents was strongly associated with regions of the annular lesions undergoing matrix reorganization consistent with an active repair response. This response extended as far as the middle third of the anulus fibrosus, which also demarcated the extent of blood vessel ingrowth and cellular infiltration in this model. The alpha-smooth muscle cell actin expression suggested an active involvement of myofibroblasts in the anulus fibrosus repair processes.

Actins↗
PubMed2002

Assessment of the cellular heterogeneity of the ovine intervertebral disc: comparison with synovial fibroblasts and articular chondrocytes.

The objective of this study was to compare and contrast the cellular heterogeneity of ovine intervertebral disc (IVD) annulus fibrosus (AF) and nucleus pulposus (NP) cells, synovial fibroblasts (SFs) and articular chondrocytes (ACs) grown in monolayer and alginate bead culture. Phase contrast microscopy of the monolayers indicated that the SF and AF cells, and the AC and NP cells had similar morphologies. Immunolocalisation of type I, II and VI collagen epitopes in the monolayers, however, demonstrated distinct quantitative and relative differences between the SF and AF, and the AC and NP cells. Immunolocalisation of bead-incorporated proteoglycans (PGs) also demonstrated quantitative and qualitative differences between the SF and AF cells. Quantitation of (35)S-bead PGs indicated that the AF cells synthesised significantly higher PG levels than the SFs, and AC cells synthesised significantly higher PG levels than the NP cells. These data were also consistent with the relative metabolic activities and cellular viabilities displayed by each cell type in bead culture. AF cells shared morphological traits with SFs in monolayer, but displayed distinctly different characteristics in bead culture. Similarly, NP cells shared similarities with ACs in monolayer and bead culture, but overall were less metabolically active. Data presented here support the proposal that the AF and NP cells of the ovine IVD should be considered as specialised fibrochondrocytic cells.

Animals↗
PubMed2002

Increased nerve and blood vessel ingrowth associated with proteoglycan depletion in an ovine anular lesion model of experimental disc degeneration.

STUDY DESIGN: Nerves and blood vessel distribution in discs were localized immunohistochemically and correlated with the proteoglycan contents of normal and degenerate disc tissues. OBJECTIVE: The aim of the present study was to systematically evaluate whether nerve and blood vessel ingrowth was associated with depletion of disc proteoglycans and degenerative changes in an established experimental model of disc degeneration. SUMMARY OF BACKGROUND DATA: Animal models of disc degeneration, allowing longitudinal study of pathogenic mechanisms, are limited. The ovine model enables systematic monitoring of blood vessel and nerve ingrowth during the development of disc degeneration after injury to the anulus fibrosus. METHODS: Merino sheep received a controlled left anterolateral surgical defect in the outer anulus fibrosus of the L1-L2 and L3-L4 discs (lesion group); sham-operated controls received the retroperitoneal anterolateral approach only. Animals were killed 3, 6, 12, and 26 months postoperation, and the discs were collected for histology and compositional and morphologic analyses. Sagittal tissue sections were stained with toluidine blue and hematoxylin and eosin; Type IV collagen immunolocalization visualized blood vessel ingrowth, and nerves were immunolocalized using monoclonal antibodies to growth-associated protein (GAP-43), protein gene product 9.5, and glial fibrillary acidic protein. RESULTS: Compositional and histologic results demonstrated early focal depletion 3-12 months postoperation of glycosaminoglycan associated with lesion development, increased blood vessel and nerve ingrowth, and infiltration of cells from the outer anulus fibrosus along the plane of the original defect. Blood vessel numbers in the outer to mid third of the anulus fibrosus were elevated in the lesion discs 3-6 months postoperation reaching a maximum at 12 months postoperation; nerves immunoreactive with protein gene product 9.5 (also maximal at 12 months postoperation) were often found associated (but not exclusively) with blood vessels, and some nerves were also reactive with GAP-43 and glial fibrillary acidic protein, but only at 12 months postoperation. CONCLUSIONS: Nerve and blood vessel ingrowth into the anulus fibrosis were strongly associated with proteoglycan depletion. The ovine anular lesion model of disc degeneration is a useful experimental model for the systematic evaluation of nerve and blood vessel development after anular injury.

Animals↗
PubMed2002

The telomeric poly(ADP-ribose) polymerase, tankyrase 1, contains multiple binding sites for telomeric repeat binding factor 1 (TRF1) and a novel acceptor, 182-kDa tankyrase-binding protein (TAB182).

Tankyrase 1, a human telomeric poly(ADP-ribose) polymerase, was originally identified through its interaction with TRF1, a negative regulator of telomere length. Tankyrase 1 ADP-ribosylates TRF1 in vitro, and its overexpression induces telomere elongation in human cancer cells. In addition to its telomeric localization, tankyrase 1 resides at multiple subcellular sites, suggesting additional functions for this protein. Here we identify TAB182, a novel tankyrase 1-binding protein of 182 kDa. TAB182 displays a complex pattern of subcellular localization. TAB182 localizes to the nucleus in a heterochromatic staining pattern and to the cytoplasm, where it co-stains with the cortical actin network. TAB182 coimmunoprecipitates with tankyrase 1 from human cells and serves as an acceptor of poly(ADP-ribosyl)ation by tankyrase 1 in vitro. Like TRF1, TAB182 binds to the ankyrin domain (comprising 24 ankyrin repeats) of tankyrase 1. Surprisingly, dissection of this domain reveals multiple discrete and overlapping binding sites for TRF1 and TAB182. Thus, we demonstrate five well conserved ankyrin repeat clusters in tankyrase 1. Although each of the five ankyrin repeat clusters independently binds to TRF1, only three of the five bind toTAB182. These findings suggest that tankyrase 1 may act as a scaffold for large molecular mass complexes made up of multiple binding proteins. We discuss potential roles for tankyrase 1-mediated higher order complexes at telomeres and at other subcellular sites.

Amino Acid Motifs↗
PubMed2002

The experience of motherhood in women with severe and enduring mental illness.

BACKGROUND: This study considers the experience of motherhood of women who are patients of the rehabilitation services in Leicester. METHOD: Data were collected from case notes, by semi-structured interviews with all women identified as mothers, and by enquiries with key workers on demographic characteristics, number of children, contact with and separations from these children, and other relationships. RESULTS: Fifty-eight women had 122 children. Of the mothers, 68 % were permanently separated from at least one child before the age of 18 years, and often had little or no subsequent contact with them. There was also attrition of other important relationships. There was scanty documentation about these issues in medical notes. CONCLUSION: Many women in long-term psychiatric care have experienced multiple losses. Clinicians should be mindful of this.

Adult↗
PubMed2002

Analysis of renal bone disease treatment in dialysis patients.

End-Stage Renal Disease Network 11 initiated a renal osteodystrophy quality improvement activity in 1999. One component was the collection and assessment of dialysis facility renal osteodystrophy protocols, whereas another component was the analysis of bone disease-related medication use. Two hundred eighty-eight facilities were invited to submit protocols. A model bone disease and mineral metabolism protocol was developed as the standard for comparison. From the model protocol, an instrument was created to evaluate eight key areas (baseline screening of key laboratory data, dietary intervention, phosphate-binder use, vitamin D use, monitoring of key laboratory indicators, management of hypercalcemia, oversuppression of parathyroid hormone [PTH], and guidelines for both hemodialysis and peritoneal dialysis patients). A bone disease-related prescription survey was completed for 749 randomly selected patients. Survey information included vitamin D and phosphate-binder use and related laboratory values (calcium, phosphorus, intact PTH [iPTH], and calcium x phosphorus product). Although 45% of facilities had six or more points on the evaluation tool, protocols were still incomplete compared with the model. Mean facility-specific scores among the five states in the Network ranged from 1.0 to 5.9 (possible scores, 0 to 8). Most patients were prescribed a phosphate binder; however, 31.8% had average phosphorus levels greater than 6.0 mg/dL during the 3-month period. Only 58% of patients with average iPTH concentrations greater than 260 pg/mL were prescribed vitamin D. Of patients treated with vitamin D, 39% had iPTH concentrations less than 130 pg/mL. There is opportunity to improve renal osteodystrophy protocols in Network 11 and reinforce potential hazards of sustained hyperphosphatemia and hyperparathyroidism.

Algorithms↗
PubMed2002

Synthesis of a Kunitz-type serine proteinase inhibitory protein that shares homology with bovine pancreatic trypsin inhibitor by ovine intervertebral disc cells in serum-free alginate bead culture.

The objective of this study was to determine whether disc cells could be cultured under serum-free conditions and whether they synthesized bovine pancreatic trypsin inhibitor (BPTI)-like serine proteinase inhibitory proteins (SPIs) previously demonstrated for ovine chondrocytes. Intervertebral discs from 1- to 2-year-old merino wether sheep were dissected into the annulus fibrosus and nucleus pulposus, and the cells isolated by sequential enzymatic digestion. The cells were grown encapsulated in calcium alginate microspheres under serum-free conditions for 10 days. They remained more than 92% viable as assessed using the vital fluorescent dyes chloromethyl fluorescein diacetate and ethidium homodimer-1 to delineate live/dead cells, respectively. Western and affinity blotting identified a 12-16-kDa media SPI and an additional 34-36-kDa BPTI-like species in solubilized bead samples. This study has demonstrated ovine disc cells synthesized BPTI-like SPIs in serum-free alginate bead culture similar to chondrocyte SPIs; however, the 58-kDa precursor SPI form was not detected suggesting differences in the endogenous processing of these SPIs.

Alginates↗
PubMed2002

Role for the related poly(ADP-Ribose) polymerases tankyrase 1 and 2 at human telomeres.

Telomere maintenance is essential for the continuous growth of tumor cells. In most human tumors telomeres are maintained by telomerase, a specialized reverse transcriptase. Tankyrase 1, a human telomeric poly(ADP-ribose) polymerase (PARP), positively regulates telomere length through its interaction with TRF1, a telomeric DNA-binding protein. Tankyrase 1 ADP-ribosylates TRF1, inhibiting its binding to telomeric DNA. Overexpression of tankyrase 1 in the nucleus promotes telomere elongation, suggesting that tankyrase 1 regulates access of telomerase to the telomeric complex. The recent identification of a closely related homolog of tankyrase 1, tankyrase 2, opens the possibility for a second PARP at telomeres. We therefore sought to establish the role of tankyrase 1 at telomeres and to determine if tankyrase 2 might have a telomeric function. We show that endogenous tankyrase 1 is a component of the human telomeric complex. We demonstrate that telomere elongation by tankyrase 1 requires the catalytic activity of the PARP domain and does not occur in telomerase-negative primary human cells. To investigate a potential role for tankyrase 2 at telomeres, recombinant tankyrase 2 was subjected to an in vitro PARP assay. Tankyrase 2 poly(ADP-ribosyl)ated itself and TRF1. Overexpression of tankyrase 2 in the nucleus released endogenous TRF1 from telomeres. These findings establish tankyrase 2 as a bona fide PARP, with itself and TRF1 as acceptors of ADP-ribosylation, and suggest the possibility of a role for tankyrase 2 at telomeres.

Cell Nucleus↗
PubMed2002

Supporting clinical leaders in achieving organisational change.

Clinical leaders in nursing may feel stuck in the middle of conflicting demands from the various members of their organisation and patients' needs. The LEO programme aims to help these clinical leaders identify their problems, agree action plans and ask for the support they need in bringing about positive change in their workplace.

Humans↗
PubMed2002

Lead screening: for the child's sake.

Lead poisoning in children can be devastating to their cognitive and behavioral development. This tragedy can be prevented with information to parents and physicians. This article summarizes the effects of lead poisoning and provides a literature review of previous studies on how often and on whom physicians should conduct blood lead level screenings. It also gives the guidelines for conducting screenings and how to process and treat the results. Health care providers are encouraged to use these guidelines for conducting screenings and follow the recommendations provided by the American Academy of Pediatrics and the Centers for Disease Control and Prevention.

Child, Preschool↗