PubMed Health⌕ Search

Biomedical subjects

Catherine Booth

Publications and source records attributed to Catherine Booth.

14 recordsLinked to original sources
PubMed2006

Müller straight stem total hip arthroplasty for fractured neck of femur.

UNLABELLED: We present the results of a retrospective review of 50 Müller straight stem total hip replacements performed for femoral neck fracture over a 10-year period. PATIENTS AND METHODS: Between 1992 and 2002, 50 Müller straight stem total hip replacements were performed for femoral neck fracture in 42 female and 8 male patients with a mean age of 74 years. RESULTS: No hips have required revision surgery. Two patients have suffered early dislocations and there have been three major medical complications. The mean Merle D'Aubigne-Postel score was 15.1. Of the 25 radiographs available for review there were no cases of radiological loosening. DISCUSSION: This is further evidence that total hip replacement in the right hands provides good results for the treatment of displaced intracapsular femoral neck fractures. The Müller straight stem gives acceptable results in a select group of patients.

Aged↗
PubMed2005

Biocompatibility and recellularization potential of an acellular porcine heart valve matrix.

BACKGROUND AND AIM OF THE STUDY: Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. The study aim was to investigate the biocompatibility and recellularization potential of an acellular porcine valve matrix. METHODS: Acellular porcine valve matrix contact and extract cytotoxicity was tested against porcine fibroblasts and smooth muscle cells (SMC). Porcine cells were incubated with decellularized aortic valve leaflets and aortic wall, and then assessed for changes in morphology and contact inhibition of growth. Soluble tissue extracts were prepared from decellularized leaflets and aortic wall, and assessed for their effect on the viability of cultured porcine cells. Acellular leaflets were seeded with either fibroblasts or SMC at 1 x 10(3) to 1 x 10(6) cells/cm2 for 24 h, or 5 x 10(4) cells/cm2 for 1-4 weeks. Cell attachment onto, and migration into, the acellular matrix was assessed by scanning electron microscopy and histology. RESULTS: No contact inhibition of growth, or changes in fibroblast or SMC morphology, were observed following contact with the acellular valve matrix. No soluble extract cytotoxicity was found. Intermediate cell-seeding densities (2.5 x 10(4) to 7.5 x 10(4) cells/cm2) of both cell types produced confluent cell attachment; at the lowest concentration (1 x 10(3) cells/cm2) cell attachment was sparse, and at the highest (1 x 10(6) cells/cm2) it was multilayered. The SMC migrated throughout the leaflet matrix over four weeks, but there was no fibroblast migration into the matrix. CONCLUSION: The absence of contact and extract cytotoxicity indicated that the acellular valve matrix was biocompatible in vitro. The failure of porcine fibroblasts to grow on, or infiltrate into, the matrix suggested that the SMC may be the preferred cell type for future leaflet recellularization studies in the development of a tissue-engineered heart valve replacement.

Animals↗
PubMed2005

Tissue engineering of cardiac valves: re-seeding of acellular porcine aortic valve matrices with human mesenchymal progenitor cells.

BACKGROUND AND AIM OF THE STUDY: Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. This study investigated the potential for re-seeding an acellular porcine heart valve matrix using human mesenchymal progenitor cells (MPC). METHODS: MPC were isolated from the bone marrow of patients undergoing hip replacement operations. Putative MPC were then cultured in several differentiation media in order to determine the multipotential differentiation capacity of the cells. The MPC were also characterized by FACS analysis. Cells at passage 8 were then seeded at between 1 x 10(4) and 1 x 10(5) cells/cm2 onto a decellularized porcine aortic valve matrix, and recellularization of the matrix was assessed. The phenotype of the re-seeded cells and re-seeded cell density was then determined by histology and immunohistochemistry. RESULTS: Putative MPC were successfully isolated and differentiated into cells of the adipogenic, neurogenic, and myogenic lineages. FACS analysis showed the cells to have a similar phenotype to those isolated by others (CD45-, CD13+, D7FIB+, CD105+, CD10+/-, LNGFR+/-, CD55+, BMP- and AP+/-). Cells seeded onto an acellular valve matrix penetrated the center of the tissue after four weeks to 2% of homograft cell density. Phenotypic analysis of the cells in the re-seeded matrix revealed the cells to have a similar phenotype to native valve interstitial cells (vimentin+, alpha-smooth muscle actin+, heavy chain myosin slow-, desmin-). However, re-seeded cells also expressed osteogenic markers (alkaline phosphatase, osteonectin, and osteopontin). CONCLUSION: This study has shown, for the first time, that human MPC have the capacity to infiltrate an acellular porcine valve matrix under static conditions in vitro. Future studies will comprise culture under pulsatile flow in a physiological heart valve bioreactor to maintain the desired cell phenotype and increase cell density.

Animals↗
PubMed2004

Pathbase: a database of mutant mouse pathology.

Pathbase is a database that stores images of the abnormal histology associated with spontaneous and induced mutations of both embryonic and adult mice including those produced by transgenesis, targeted mutagenesis and chemical mutagenesis. Images of normal mouse histology and strain-dependent background lesions are also available. The database and the images are publicly accessible (http://www.pathbase.net) and linked by anatomical site, gene and other identifiers to relevant databases; there are also facilities for public comment and record annotation. The database is structured around a novel ontology of mouse disorders (MPATH) and provides high-resolution downloadable images of normal and diseased tissues that are searchable through orthogonal ontologies for pathology, developmental stage, anatomy and gene attributes (GO terms), together with controlled vocabularies for type of genetic manipulation or mutation, genotype and free text annotation for mouse strain and additional attributes. The database is actively curated and data records assessed by pathologists in the Pathbase Consortium before publication. The database interface is designed to have optimal browser and platform compatibility and to interact directly with other web-based mouse genetic resources.

Animals↗
PubMed2003

Poly(ADP-ribose) polymerase-1 is a survival factor for radiation-exposed intestinal epithelial stem cells in vivo.

Poly(ADP-ribose) polymerase-1 (PARP-1) is a key enzyme mediating the cellular response to DNA strand breaks. It plays a critical role in genomic stability and survival of proliferating cells in culture undergoing DNA damage. Intestinal epithelium is the most proliferative tissue in the mammalian body and its stem cells show extreme sensitivity to low-level genotoxic stress. We investigated the role of PARP-1 in the in vivo damage response of intestinal stem cells in crypts of PARP-1-/- and control mice following whole-body gamma-irradiation (1 Gy). In the PARP-1-/- mice there was a significant delay during the first 6 h in the transient p53 accumulation in stem cells whereas an increased number of cells were positive for p21(CIP1/WAF1). Either no or only marginal differences were noted in MDM2 expression, apoptosis, induction of or recovery from mitotic blockage, or inhibition of DNA synthesis. We further observed a dose-dependent reduction in crypt survival measured at 4 days post-irradiation in control mice, and this crypt-killing effect was significantly potentiated in PARP-1-/- mice. Our results thus establish that PARP-1 acts as a survival factor for intestinal stem cells in vivo and suggest a functional link with early p53 and p21(CIP1/WAF1) responses.

Animals↗
PubMed2003

The small intestine as a model for evaluating adult tissue stem cell drug targets.

Adult tissue stem cells are defined and some current controversies are discussed. These crucial cells are responsible for all cell production in renewing tissues, and play a vital role in tissue regeneration. Although reliable stem cell markers are generally unavailable for adult epithelial tissues, the small intestinal crypts are an excellent in vivo model system to study stem cells. Within this tissue, the stem cells have a very well-defined cell position, allowing accurate definition of stem cell specific events. Clonal regeneration assays for the small intestine allow stem cell survival and functional competence to be studied. The ultimate lineage ancestor stem cells are extremely efficiently protected from genetic damage, which accounts for the low cancer incidence in this tissue. Some of the regulatory networks governing stem and transit cell behaviour are beginning to be understood and it is postulated that p53 plays a crucial role in these processes.

Adult↗
PubMed2003

Identification of a putative intestinal stem cell and early lineage marker; musashi-1.

There are few reliable markers for adult stem cells and none for those of the intestinal epithelium. Previously, indirect experimental approaches have predicted stem cell position and numbers. The Musashi-1 (Msi-1) gene encodes an RNA binding protein associated with asymmetric divisions in neural progenitor cells. Two-day-old, adult, and 4.5 h, 1-, 2-, 4- and 12-day post-irradiation samples of BDF1 mouse small intestine, together with some samples of mouse colon were stained with a rat monoclonal antibody to Musashi-1 (14 H-1). Min ( + / - ) mice with small intestinal adenomas of varying sizes were also analysed. Samples of human small and large bowel were also studied but the antibody staining was weak. Musashi-1 expression was observed using immunohistochemistry in neonatal, adult, and regenerating crypts with a staining pattern consistent with the predicted number and distribution of early lineage cells including the functional stem cells in these situations. Early dysplastic crypts and adenomas were also strongly Musashi-1 positive. In situ hybridization studies showed similar expression patterns for the Musashi mRNA and real-time quantitative RT-PCR showed dramatically more Msi-1 mRNA expression in Min tumours compared with adjacent normal tissue. These observations suggest that Musashi-1 is a marker of stem and early lineage progenitor cells in murine intestinal tissue.

Adult↗
PubMed2002

The intestinal epithelial stem cell.

This article considers the role of the adult epithelial stem cell, with particular reference to the intestinal epithelial stem cell. Although the potential of adult stem cells has been revealed in a number of recent publications, the organization and control of the stem cell hierarchy in epithelial tissues is still not fully understood. The intestinal epithelium is an excellent model in which to study such hierarchies, having a distinctive polarity and high rate of cell proliferation and migration. Studies on the small intestinal crypt provide insight into the characteristics of the stem cells in normal and regenerating circumstances and demonstrate why a thorough understanding of these cells is an essential pre-requisite for stem cell based therapeutic approaches.

Adult↗
PubMed2002

Towards defining roles and relationships for tenascin-C and TGFbeta-1 in the normal and neoplastic urinary bladder.

Tenascin-C (TN-C) is an extracellular matrix glycoprotein expressed along epithelial/stromal boundaries during tissue remodelling events, such as those that occur during morphogenesis, wound healing, and tumour invasion. Using clinical specimens and a range of in vitro models that simulate homeostasis, wound healing, and malignant progression, this study sought to establish the patterns of TN-C expression in normal and neoplastic bladder and to determine the role of exogenous transforming growth factor beta-1 (TGFbeta-1), interleukin-4 (IL-4), basic fibroblast growth factor (bFGF), tumour necrosis factor alpha (TNFalpha), and interferon gamma (IFNgamma) in the induction of TN-C expression by bladder uro-epithelial cells. The findings indicate that normal urothelial cells may express TN-C, with both TGFbeta-1 and IL-4 able to induce expression. TN-C was not expressed in neoplastic urothelium, although both TN-C and TGFbeta-1 may be involved in tissue remodelling during papillary tumour formation and invasion. Furthermore, the urothelium of high-grade papillary tumours and carcinoma in situ specimens exhibited little TGFbeta-1 immunoreactivity, compared with the urothelium of low-grade tumours and normal specimens, suggesting an association between TGFbeta-1 expression and urothelial differentiation. A tumour invasion model, in which established bladder cancer cell lines were seeded onto a normal bladder stroma, corroborated the evidence from the clinical specimens and demonstrated that TN-C was strongly expressed around foci of stromal invasion. Thus, TN-C immunoreactivity may provide an additional tool in the assessment of early stromal invasion in bladder cancer.

Biomarkers, Tumor↗
PubMed2002

Keratinocyte stem cells: a commentary.

For many years it has been widely accepted that stem cells play a crucial role in adult tissue maintenance. The concept that the renewing tissues of the body contain a small subcompartment of self-maintaining stem cells, upon which the entire tissue is dependent, is also now accepted as applicable to all renewing tissues. Gene therapy and tissue engineering are driving considerable interest in the clinical application of such hierarchically organized cellular compartments. Recent initial observations have provided a tantalizing insight into the large pluripotency of these cells. Indeed, scientists are now beginning to talk about the possible totipotency of some adult tissue stem cells. Such work is currently phenomenologic, but analysis of data derived from genomics and proteomics, identifying the crucial control signals involved, will soon provide a further impetus to stem cell biology with far reaching applications. The epidermis with its relatively simple structure, ease of accessibility, and the ability to grow its cells in vitro is one obvious target tissue for testing stem cell manipulation theories. It is crucial, however, that the normal keratinocyte stem cell is thoroughly characterized prior to attempting to manipulate its pluripotency. This commentary assesses the data generated to date and critically discusses the conclusions that have been drawn. Our current level of understanding, or lack of understanding, of the keratinocyte stem cell is reviewed.

Biomarkers↗
PubMed2002

Tissue engineering of cardiac valve prostheses I: development and histological characterization of an acellular porcine scaffold.

BACKGROUND AND AIMS OF THE STUDY: Several deficiencies in current heart valve prostheses make them problematic for use in younger patients. Tissue valve substitutes are non-viable with a life expectancy of only 10-15 years, while mechanical valves require long-term anti-coagulation therapy. A solution to these problems would be to develop a tissue-engineered heart valve containing autologous cells, enabling the valve to maintain its biochemical and mechanical properties, yet grow with the patient. The study aim was to optimize a protocol to produce a porcine acellular matrix scaffold for use in developing a tissue-engineered heart valve. METHODS: Fresh porcine aortic valve leaflets were treated with Triton X-100, sodium dodecyl sulfate (SDS), sodium deoxycholate, MEGA 10, TnBP, CHAPS, and Tween 20, over a range of concentrations, in the presence of protease inhibitors for up to 72 h. Histological analysis was used to detect the major structural proteins of the heart valve, collagen I, elastin and glycosaminoglycans. RESULTS: After 72 h, most protocols resulted in the retention of large numbers of whole cells and cell fragments. Only SDS (0.03-1%) or sodium deoxycholate (0.5-2%) resulted in total decellularization at 24 h. Histological analysis of acellular matrices showed that the major structural proteins had been retained and appeared to be intact. CONCLUSION: Protocols utilizing SDS or sodium deoxycholate were successful for leaflet decellularization, and histological analysis showed that the major structural components of the valve matrix had been maintained. These methods are being developed further with a view to reseeding with autologous cells to produce tissue-engineered solutions for clinical implantation.

Animals↗
PubMed2002

Tissue engineering of cardiac valve prostheses II: biomechanical characterization of decellularized porcine aortic heart valves.

BACKGROUND AND AIMS OF THE STUDY: For both young patients with congenital heart disease and young, growing adults there is a need for replacement heart valves that will develop with the patient. Tissue-engineered heart valves coupled with in-vitro recellularization have this potential. One approach is to use acellular tissue matrices, but the decellularization treatment must not affect the biomechanical integrity of the valvular matrix. This study investigated the effect of 0.03% (w/v) and 0.1% (w/v) sodium dodecyl sulfate (SDS) on the mechanical integrity of porcine aortic valve leaflets. METHODS: Left coronary porcine leaflets were treated with SDS (0.03% or 0.1%, w/v) in hypotonic or isotonic buffer and buffer alone. SDS in hypotonic buffer produced accellularity. Circumferential and radial specimens of treated leaflets were subjected to uniaxial tensile testing, and the effect of the buffer on leaflet morphology was assessed. Whole porcine aortic roots were also treated with 0.1% (w/v) SDS and subjected to function testing. RESULTS: SDS treatment significantly increased extensibility of the leaflet specimens, which was greater in the circumferential than radial direction. This was seen as a significantly decreased slope of both the elastic and collagen phases of the stress-strain behavior. The ultimate tensile strength and transition stress were not affected significantly; nor was there any significant difference between hypotonic buffer and hypotonic buffer + SDS treatments. Study of the leaflet morphology suggested that the increased extensibility was due to shrinkage as well as to increased hydration of the treated leaflets caused by the hypotonic buffer. CONCLUSION: SDS treatment produced a more extensible tissue with equal strength compared with the fresh aortic valve. Functionality experiments with SDS-treated whole aortic roots showed complete valve leaflet competence under physiological pressures (120 mmHg) as well as physiological leaflet kinematics.

Animals↗
PubMed2002

The pulmonary bioprosthetic heart valve: its unsuitability for use as an aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: The porcine pulmonary bioprosthetic heart valve represents an alternative means of aortic valve replacement (AVR), though knowledge of its biomechanical function and characteristics is limited. The valve has potential advantages over the aortic bioprosthesis; notably, it lacks the muscular shelf of the right coronary cusp of the latter bioprosthesis. The study aim was to investigate the suitability of the porcine pulmonary bioprosthetic valve for AVR. METHODS: Porcine pulmonary and aortic roots were zero pressure-fixed with 0.5% buffered glutaraldehyde, characterized, and compared with fresh porcine pulmonary and aortic roots. The in-vitro analysis included assessment of mechanical properties, hydrodynamic function, geometry of the pulmonary root, and durability. RESULTS: The fixed pulmonary roots and fresh aortic roots were similar in certain aspects of mechanical response, notably leaflets in the radial direction and the root wall. The fixed pulmonary root was slightly more compliant than the fixed aortic root, and this led to an improvement in forward flow hydrodynamic function. The reverse flow hydrodynamic function of the pulmonary roots was poor; fresh pulmonary roots exhibited a trivial closed valve regurgitant volume. On fixation, this characteristic was aggravated, leading to a gross closed valve regurgitant volume in 50% of all fixed pulmonary roots. The cause of leakage was identified as a prolapsed anterior leaflet. Durability of the fixed pulmonary root was also inferior to that of the fixed aortic root; three fixed pulmonary roots subjected to accelerated fatigue testing showed signs of leaflet macroscopic damage. CONCLUSION: Overall, the performance of the porcine pulmonary bioprosthesis was far inferior to that of the currently used porcine aortic bioprosthesis. Hence, the porcine pulmonary bioprosthetic valve was deemed unsuitable for AVR.

Animals↗