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P Robbins

Publications and source records attributed to P Robbins.

At least 19 recordsLinked to original sources
PubMed2006

Direct adenoviral transfer of bone morphogenetic protein-2 cDNA enhances fracture healing in osteoporotic sheep.

Osteoporosis, a major public health burden, is associated with increased fracture risk. Fracture healing in osteoporosis is delayed, with reduced callus formation and impaired biomechanical properties of newly formed bone leading to high risk of fixation failure. Adenoviral gene transfer of bone morphogenetic protein-2 (BMP-2) has been shown to enhance fracture healing. This study evaluated the ability of gene transfer to enhance bone healing in osteoporosis. An established sheep model of osteoporosis with well-characterized alterations in fracture healing was used. Osteotomies were created surgically in the tibias of adult female sheep and monitored for 8 weeks, using radiographic, biomechanical, and histological methods. For pilot experiments, primary ovine osteoblasts and mesenchymal stem cells were transduced with a recombinant adenovirus carrying BMP-2 cDNA (Ad.BMP-2). Large increases in alkaline phosphatase production and mineralization confirmed the ability of human BMP-2 to stimulate osteoblastic differentiation in sheep. In vivo bending stiffness measurements during fracture healing as well as ex vivo torsional stiffness measurements demonstrated stiffer callus tissue after treatment with Ad.BMP-2. The differences were found mainly in the early fracture-healing period. Computed tomography demonstrated that animals receiving the BMP-2 cDNA had larger cross-sectional callus area and higher callus density. Histological examination of the tibias confirmed enhanced callus formation. Direct, local adenoviral delivery of an osteogenic gene thus led to enhanced healing of fractures in an ovine model of osteoporosis. These promising data encourage the further development of genetic approaches to enhance bone healing in patients suffering osteoporosis-associated fractures.

Adenoviridae↗
PubMed2003

Predicting the HER2 status of breast cancer from basic histopathology data: an analysis of 1500 breast cancers as part of the HER2000 International Study.

The tests that are currently available for the measurement of overexpression of the human epidermal growth factor-2 (HER2) in breast cancer have shown considerable problems in accuracy and interlaboratory reproducibility. Although these problems are partly alleviated by the use of validated, standardised 'kits', there may be considerable cost involved in their use. Prior to testing it may therefore be an advantage to be able to predict from basic pathology data whether a cancer is likely to overexpress HER2. In this study, we have correlated pathology features of cancers with the frequency of HER2 overexpression assessed by immunohistochemistry (IHC) using HercepTest (Dako). In addition, fluorescence in situ hybridisation (FISH) has been used to re-test the equivocal cancers and interobserver variation in assessing HER2 overexpression has been examined by a slide circulation scheme. Of the 1536 cancers, 1144 (74.5%) did not overexpress HER2. Unequivocal overexpression (3+ by IHC) was seen in 186 cancers (12%) and an equivocal result (2+ by IHC ) was seen in 206 cancers (13%). Of the 156 IHC 3+ cancers for which complete data was available, 149 (95.5%) were ductal NST and 152 (97%) were histological grade 2 or 3. Only 1 of 124 infiltrating lobular carcinomas (0.8%) showed HER2 overexpression. None of the 49 'special types' of carcinoma showed HER2 overexpression. Re-testing by FISH of a proportion of the IHC 2+ cancers showed that only 25 (23%) of those assessable exhibited HER2 gene amplification, but 46 of the 47 IHC 3+ cancers (98%) were confirmed as showing gene amplification. Circulating slides for the assessment of HER2 score showed a moderate level of agreement between pathologists (kappa 0.4). As a result of this study we would advocate consideration of a triage approach to HER2 testing. Infiltrating lobular and special types of carcinoma may not need to be routinely tested at presentation nor may grade 1 NST carcinomas in which only 1.4% have been shown to overexpress HER2. Testing of these carcinomas may be performed when HER2 status is required to assist in therapeutic or other clinical/prognostic decision-making. The highest yield of HER2 overexpressing carcinomas is seen in the grade 3 NST subgroup in which 24% are positive by IHC.

Adult↗
PubMed2001

Transforming growth factor-beta1 increases survival of human melanoma through stroma remodeling.

Transforming growth factor (TGF)-beta is growth inhibitory for normal epithelial cells and melanocytes but can stimulate mesenchymal cells. Resistance to its inhibitory effects is characteristic of human melanoma, the growth of which may instead be promoted by TGF-beta, because its production is increased with melanoma progression. Whether TGF-beta has an autocrine function for melanoma cells or is important for paracrine stimulation of the tumor stroma is not known. In this study, TGF-beta1 was expressed in melanoma cells via adenoviral gene transfer, and tumor growth was analyzed in vitro, in human skin grafts, and in mixtures with fibroblasts that were injected s.c. into immunodeficient mice. The TGF-beta1 produced by the melanoma cells activated the fibroblasts to produce matrix within and around the tumor mass, whereas control tumors showed less stroma and more cell death. High expression of collagen, fibronectin, tenascin, and alpha2 integrin was detected in the TGF-beta1-expressing tumors by immunohistochemistry. Number and size of lung metastases were significantly increased. cDNA expression array analysis of TGF-beta1-transduced fibroblasts embedded in type I collagen and of TGF-beta1-transduced melanoma cells demonstrated induction of types XV, XVIII, and VI collagens, tenascin, plasminogen activator inhibitor-I, vascular endothelial growth factor, cysteine-rich fibroblast growth factor receptor-1, and platelet-derived growth factor receptor-beta, which could be linked to promotion of growth and survival in melanoma. These data suggest that remodeling of the neighboring stroma, which provides a supporting scaffolding and a positive feedback stimulation of tumor growth, is an important function of TGF-beta1 in melanoma.

Animals↗
PubMed2001

Lhermitte-Duclos disease associated with Cowden's syndrome: case report and literature review.

Lhermitte-Duclos disease (LDD) is a rare entity that may occur in the setting of Cowden's syndrome (CS). Accurate preoperative diagnosis can be made on the characteristic CT and MR appearances, thereby obviating the need for biopsy. It is important to be aware of the link between LDD and CS so that appropriate genetic counselling and tumour surveillance can be undertaken.

Adult↗
PubMed2001

Effects of different concentrations of sevoflurane and desflurane on subcortical somatosensory evoked responses in anaesthetized, non-stimulated patients.

Twenty-four patients were recruited and given either sevoflurane or desflurane as their sole anaesthetic. Each patient was given sequentially increasing or decreasing doses at 0.5 MAC intervals, and the median nerve somatosensory evoked response recorded after an equilibration at each concentration. The N20-P25 and P25-N35 amplitudes decreased with increasing agent concentration. However, for both agents the P15-N20 amplitude response was quadratic in shape. The peak inflection points were at 3.2% for sevoflurane and 4.9% for desflurane. There were no differences between the ascending and descending groups. This increase in activity in the midbrain at 'surgical' end-tidal anaesthetic concentrations suggests more complex neuroelectrical responses to anaesthesia than simple global suppression.

Adult↗
PubMed2001

The histogenesis of giant cell tumour of bone: a model of interaction between neoplastic cells and osteoclasts.

Giant cell tumour of bone (GCT) is a benign primary neoplasm of a bone characterised by distinctive clinical, radiological and pathological features. Females are slightly more often affected than males, and the majority of patients present between the ages of 20 and 50. GCT is locally aggressive and produces expansive and lytic lesions, most commonly in the epiphyses of long tubular bones. Histologically, it is composed of oval and spindle mononuclear cells, uniformly distributed amongst which are large multinucleated osteoclast-like giant cells. Although the term "Giant Cell Tumour" (and the erroneous historical term 'osteoclastoma') may imply that it is the multinucleated giant cells which are responsible for the proliferative capacity of the tumour, there is evidence that the stromal-like cells, the major component of the mononuclear cell population, represent the true neoplastic component of the neoplasm. The diagnosis and management of conventional GCT are often challenging and there is considerable current interest in its pathobiology. The precise histogenesis of GCT and the nature of its varying cellular constituents have remained a matter of some controversy. Factors influencing the clinical course and biological aggression of GCT are also unclear. In this selective review, the clinicopathological characteristics of GCT are summarised and current areas of interest in the study of the neoplasm are presented and discussed. Lastly, a hypothetical model of the mechanism of histogenesis and the biological behaviour of GCT is presented.

Animals↗
PubMed2001

Effect of bone morphogenetic protein-2-expressing muscle-derived cells on healing of critical-sized bone defects in mice.

BACKGROUND: Cells that express bone morphogenetic protein-2 (BMP-2) can now be prepared by transduction with adenovirus containing BMP-2 cDNA. Skeletal muscle tissue contains cells that differentiate into osteoblasts on stimulation with BMP-2. The objectives of this study were to prepare BMP-2-expressing muscle-derived cells by transduction of these cells with an adenovirus containing BMP-2 cDNA and to determine whether the BMP-2-expressing muscle-derived cells would elicit the healing of critical-sized bone defects in mice. METHODS: Primary cultures of muscle-derived cells from a normal male mouse were transduced with adenovirus encoding the recombinant human BMP-2 gene (adBMP-2). These cells (5 yen 10(5)) were implanted into a 5-mm-diameter critical-sized skull defect in female SCID (severe combined immunodeficiency strain) mice with use of a collagen sponge as a scaffold. Healing in the treatment and control groups was examined grossly and histologically at two and four weeks. Implanted cells were identified in vivo with use of the Y-chromosome-specific fluorescent in situ hybridization (FISH) technique, and their differentiation into osteogenic cells was demonstrated by osteocalcin immunohistochemistry. RESULTS: Skull defects treated with muscle cells that had been genetically engineered to express BMP-2 had >85% closure within two weeks and 95% to 100% closure within four weeks. Control groups in which the defect was not treated (group 1), treated with collagen only (group 2), or treated with collagen and muscle cells without adBMP-2 (group 3) showed at most 30% to 40% closure of the defect by four weeks, and the majority of the skull defects in those groups showed no healing. Analysis of injected cells in group 4, with the Y-chromosome-specific FISH technique showed that the majority of the transplanted cells were located on the surfaces of the newly formed bone, but a small fraction (approximately 5%) was identified within the osteocyte lacunae of the new bone. Implanted cells found in the new bone stained immunohistochemically for osteocalcin, indicating that they had differentiated in vivo into osteogenic cells. CONCLUSIONS: This study demonstrates that cells derived from muscle tissue that have been genetically engineered to express BMP-2 elicit the healing of critical-sized skull defects in mice. The cells derived from muscle tissue appear to enhance bone-healing by differentiating into osteoblasts in vivo. CLINICAL RELEVANCE: Ex vivo gene therapy with muscle-derived cells that have been genetically engineered to express BMP-2 may be used to treat nonhealing bone defects. In addition, muscle-derived cells appear to include stem cells, which are easily obtained with muscle biopsy and could be used in gene therapy to deliver BMP-2.

Animals↗
PubMed2000

Clonal isolation of muscle-derived cells capable of enhancing muscle regeneration and bone healing.

Several recent studies suggest the isolation of stem cells in skeletal muscle, but the functional properties of these muscle-derived stem cells is still unclear. In the present study, we report the purification of muscle-derived stem cells from the mdx mouse, an animal model for Duchenne muscular dystrophy. We show that enrichment of desmin(+) cells using the preplate technique from mouse primary muscle cell culture also enriches a cell population expressing CD34 and Bcl-2. The CD34(+) cells and Bcl-2(+) cells were found to reside within the basal lamina, where satellite cells are normally found. Clonal isolation and characterization from this CD34(+)Bcl-2(+) enriched population yielded a putative muscle-derived stem cell, mc13, that is capable of differentiating into both myogenic and osteogenic lineage in vitro and in vivo. The mc13 cells are c-kit and CD45 negative and express: desmin, c-met and MNF, three markers expressed in early myogenic progenitors; Flk-1, a mouse homologue of KDR recently identified in humans as a key marker in hematopoietic cells with stem cell-like characteristics; and Sca-1, a marker for both skeletal muscle and hematopoietic stem cells. Intramuscular, and more importantly, intravenous injection of mc13 cells result in muscle regeneration and partial restoration of dystrophin in mdx mice. Transplantation of mc13 cells engineered to secrete osteogenic protein differentiate in osteogenic lineage and accelerate healing of a skull defect in SCID mice. Taken together, these results suggest the isolation of a population of muscle-derived stem cells capable of improving both muscle regeneration and bone healing.

Alkaline Phosphatase↗
PubMed2000

A tumor-infiltrating lymphocyte from a melanoma metastasis with decreased expression of melanoma differentiation antigens recognizes MAGE-12.

Twenty separate tumor infiltrating lymphocyte (TIL) bulk cultures and a tumor cell line were originated simultaneously from a fine needle aspiration biopsy of a metastasis in a patient with melanoma (F001) previously immunized with the HLA-A*0201-associated gp100:209-217(210 M) peptide. None of the TIL recognized gp100. However, 12 recognized autologous (F001-MEL) and allogeneic melanoma cells expressing the HLA haplotype A*0201, B*0702, Cw*0702. Further characterization of F001-MEL demonstrated loss of gp100/PMel17, severely decreased expression of other melanoma differentiation Ags and retained expression of tumor-specific Ags. Transfection of HLA class I alleles into B*0702/Cw*0702-negative melanoma cell lines identified HLA-Cw*0702 as the restriction element for F001-TIL. A cDNA library from F001-MEL was used to transfect IFN-alpha-stimulated 293 human embryonal kidney (293-HEK) cells expressing HLA-Cw*0702. A 100-gene pool was identified that induced recognition of 293-HEK cells by F001-TIL. Subsequent cloning of the pool identified a cDNA sequence homologous, except for one amino acid (aa 187 D-->A), to MAGE-12. Among 25 peptide sequences from MAGE-12 with the HLA-Cw*0702 binding motif, MAGE-12:170-178 (VRIGHLYIL) induced IFN-gamma release by F001-TIL when pulsed on F001-EBV-B cells at concentrations as low as 10 pg/ml. Peptide sequences from MAGE-1, 2, 3, 4a, and 6 aligned to MAGE-12:170-178 were not recognized by F001-TIL. In summary a TIL recognizing a MAGE protein was developed from an HLA-A*0201 expressing tumor with strongly reduced expression of melanoma differentiation Ags. Persisting tumor-specific Ag expression maintained tumor immune competence suggesting that tumor-specific Ags/melanoma differentiation Ags may complement each other in the context of melanoma Ag-specific vaccination.

Alleles↗
PubMed2000

Nuclear beta-catenin displays GSK-3beta- and APC-independent proteasome sensitivity in melanoma cells.

Colon carcinoma and melanoma cells containing either a deletion of the adenomatous polyposis coli tumor suppressor protein (APC) or mutation of the site in beta-catenin phosphorylated by glycogen synthase kinase-3beta (GSK-3beta) display elevated levels of detergent-soluble beta-catenin due to insensitivity of the cytosolic protein to proteasome-dependent degradation. In this study, we have examined the effect of beta-catenin mutation (S37F) or APC loss on the proteasome sensitivity of additional subcellular beta-catenin pools in melanoma cells. In contrast to detergent-soluble beta-catenin, the detergent-insoluble protein remains proteasome-sensitive irrespective of S37F mutation or APC status. This insoluble component appears associated primarily with nuclear cytoskeletal elements. In addition, DNase I treatment solubilized a portion of detergent-insoluble beta-catenin, suggesting that this fraction also contains chromatin-associated protein, and correlating with a proteasome-sensitive elevation in beta-catenin-stimulated reporter activity. Since the detergent-insoluble nuclear component of beta-catenin displays GSK-3beta- and APC-independent proteasome sensitivity, distinct from the soluble nuclear and cytosolic pools of this protein, regulation of beta-catenin proteasome sensitivity and the contribution of this process to beta-catenin function may be more complex than previously appreciated.

Adenomatous Polyposis Coli Protein↗
PubMed2000

CD4(+), HLA class I-restricted, cytolytic T-lymphocyte clone against primary malignant melanoma cells.

The involvement of HLA-class I in target cell lysis by CD4(+) cytolytic T cells (CTL) has been a controversial issue. A CTL clone of CD4 phenotype was derived from the peripheral blood lymphocytes of a patient with primary melanoma. The CTL clone stably lysed the autologous primary melanoma cells for approximately 9 months in culture. Both the Valpha2/Vbeta8 T-cell receptor and CD4 were involved in CTL cytotoxicity. Of a large panel of allogeneic primary and metastatic melanoma or colorectal carcinoma cells, autologous and allogeneic Epstein-Barr virus-transformed B cells and autologous fibroblasts, only allogeneic metastatic melanoma cells matched with the autologous tumor cells for HLA-class I (B57[17]) were lysed and induced IFN-gamma secretion by the CTL clone. Lysis of the autologous tumor cells was significantly blocked by monoclonal antibody to HLA-B17. Importantly, allogeneic, HLA-class I- and class II-unmatched melanoma cells were lysed by the CTL only following transfection of the cells with B57[17] cDNA. Our results provide direct evidence for the involvement of both CD4 and HLA-class I in tumor cell lysis by CD4(+) CTL.

Adult↗
PubMed2000

Can p53 alterations be used to predict tumour response to pre-operative chemo-radiotherapy in locally advanced rectal cancer?

PURPOSE: To examine whether p53 tumour suppressor gene alterations can be used to predict tumour response to pre-operative chemo-radiation in locally advanced rectal cancer in terms of reduction in tumour size and local failure. METHODS: p53 alterations were studied in pre-treatment biopsy specimens of rectal carcinomas from 48 patients by immunohistochemistry (IHC) and polymerase chain reaction/single strand conformation polymorphism (PCR-SSCP) gene mutation analysis. Pre-operative pelvic radiotherapy was delivered with four fields, 45 Gy to the ICRU point in 25 fractions over 5 weeks. A radio-sensitising dose of 5-fluorouracil (500 mg/m(2)) was delivered concurrently for 6 days of the 5-week schedule (days 1, 2, 3 and days 22, 23 and 24). Total meso-rectal excision was planned 4 to 6 weeks from completion of pre-operative treatment. Response to therapy was assessed by macroscopic measurement of the surgical specimen by a pathologist who was unaware of the pre-treatment tumour size or of the p53 status. RESULTS: IHC evidence of p53 protein accumulation was found in 40% of tumours, p53 gene mutation in 35% and p53 alteration (either or both changes) in 46%. The average reduction in tumour size was 53% in the group with 'wild-type' p53 (IHC-/SSCP-) and 63% in the group with altered p53 (either IHC+ or SSCP+; P=0.18). No significant differences in tumour size reduction or local failure were observed in the groups with p53 overexpression or p53 mutation compared with normal. CONCLUSIONS: p53 alteration detected by IHC or SSCP analysis is not a clinically useful predictor of local response to pre-operative adjuvant therapy in advanced rectal carcinoma.

Adenocarcinoma↗
PubMed2000

Prevention of beta cell dysfunction and apoptosis activation in human islets by adenoviral gene transfer of the insulin-like growth factor I.

Interleukin-1beta is a potent pro-inflammatory cytokine that has been shown to inhibit islet beta cell function as well as to activate Fas-mediated apoptosis in a nitric oxide-dependent manner. Furthermore, this cytokine is effective in recruiting lymphocytes that mediate beta cell destruction in IDDM onset. The insulin-like growth factor I (IGF-I) has been shown to block IL-1beta actions in vitro. We hypothesized that gene transfer of the insulin-like growth factor I to intact human islets could prevent IL-1beta-induced beta cell dysfunction and sensitization to Fas-triggered apoptosis activation. Intact human islets were infected with adenoviral vectors encoding IGF-I as well as beta-galactosidase and enhanced green fluorescent protein as controls. Adenoviral gene transfer of human IGF-I prevented IL-1beta-mediated nitric oxide production from human islets in vitro as well as the suppression of beta cell function as determined by glucose-stimulated insulin production. Moreover, IGF-I gene transfer prevented IL-1beta-induced, Fas-mediated apoptosis. These results suggest that locally produced IGF-I from cultured islets may be beneficial in maintaining beta cell function and promoting islet survival before and following islet transplantation as a potential therapy for type I diabetes.

Adenoviridae↗
PubMed2000

Gene expression of vascular endothelial growth factor in giant cell tumors of bone.

The production of vascular endothelial growth factors (VEGF), a major cause of neoangiogenesis, is a prerequisite for tumor growth and invasion. VEGF have also been shown to be important for the formation of osteoclasts. Because giant cell tumors of bone (GCT) are frequently hypervascular and have the ability to recruit macrophages and multinucleated osteoclast-like giant cells, we evaluated the levels of VEGF gene transcript in several of these tumors using Northern blot analyses, semiquantitative reverse transcription polymerase chain reaction (RT-PCR), fluorescence in situ hybridization (FISH), and immunohistochemistry. Our results showed that three major isoforms of VEGF (121, 165, and 189) were expressed in all cases of GCT investigated, with isoform 121 transcripts the most abundant. By both FISH and immunohistochemistry, we have shown that VEGF was present in spindle-shaped stromal-like tumor cells, round macrophage-like cells, and osteoclast-like multinucleate giant cells. Moreover, we have shown that the levels of VEGF gene expression but not microvessel density correlated with Enneking's clinical stage of GCT. There were higher levels of VEGF gene expression in stage III GCT than in stage I/II GCT (P < .0357). In conclusion, our results indicate that overexpression of VEGF may be associated with the advanced stage of the neoplasm.

Adult↗
PubMed2000

Assessment of endothelial cell proliferation in primary breast carcinoma and its association with axillary lymph node status.

The correlation between angiogenesis as assessed by endothelial cell proliferation in blood/lymphatic vessels in primary breast carcinomas, and axillary lymph-node metastasis was studied using a case-control design. Primary breast carcinomas, < 2 cm in diameter, from 26 axillary node positive patients (case), were compared with neoplasms from 45 node-negative patients (control). Vascularity, as assessed by vessel density, and endothelial cell proliferation were measured in a single tissue section using a double immunohistochemical staining technique using MIBI (Ki-67) and FVIII antibodies. No association between vascularity and node status was found (P > 0.70). Node positive breast carcinomas had, on average, significantly smaller proliferating vessels (140+/-7 microm in perimeter) in the primary lesion when compared with node negative tumours (164+/-7 microm in perimeter (P < 0.02). In addition, the frequency of relatively small vessels (less than 180 microm in perimeter) with proliferating endothelium was higher in node positive carcinomas than lymph-node negative neoplasms (P < 0.03). This association between node status and the size and frequency of blood/lymphatic vessels with proliferating endothelium in primary carcinoma may have important implications in metastasis.

Journal Article↗