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P R Cooper

Publications and source records attributed to P R Cooper.

At least 19 recordsLinked to original sources
PubMed2026

ARID1A Mediates ROS-Induced Osteoclast Activation in TMJ Osteoarthritis.

Excessive osteoclast activation drives rapid subchondral bone destruction, serving as a critical early-stage event precipitating temporomandibular joint osteoarthritis (TMJ-OA). Although epigenetic remodeling is widely recognized as an important interface between pathological environmental signals and genomic response, the specific epigenetic mechanisms translating TMJ-OA-associated stimulation into pathological osteoclast activation remain to be elucidated. Here, using a mechanically induced TMJ-OA mouse model, we identify aberrant reactive oxygen species (ROS) accumulation as a critical upstream driver initiating excessive osteoclast activation and subsequent joint deterioration. By integrating transcriptomic and epigenomic analyses, we delineate the chromatin remodeler AT-rich interaction domain 1A (ARID1A) as an essential oxidative stress sensor within the osteoclast lineage. Mechanistically, ROS accumulation induces ARID1A upregulation and recruitment to the Src enhancer, transcriptionally activating Src and amplifying PI3K-AKT signaling to drive pathological osteoclastogenesis. Conditional knockout of Arid1a in myeloid cells effectively abrogates subchondral bone loss and cartilage destruction in TMJ-OA. Translating these mechanistic insights, we engineered an ROS-responsive, osteoclast-targeting hydrogel for the on-demand delivery of an ARID1A-dependent canonical BRG1/BRM-associated factor complex inhibitor, which successfully alleviates TMJ-OA progression. Our findings establish the epigenetic response to ROS accumulation as a key pathogenic mechanism in TMJ-OA and highlight ARID1A as a promising therapeutic target for early disease intervention.

biomaterial(s)↗
PubMed2007

Hyperactivity and reactivity of peripheral blood neutrophils in chronic periodontitis.

Some evidence exists that peripheral neutrophils from patients with chronic periodontitis generate higher levels of reactive oxygen species (ROS) after Fcgamma-receptor stimulation than those from healthy controls. We hypothesized that peripheral neutrophils in periodontitis also show both hyper-reactivity to plaque organisms and hyperactivity in terms of baseline, unstimulated generation and release of ROS. Peripheral neutrophils from chronic periodontitis patients and age/sex/smoking-matched healthy controls (18 pairs) were assayed for total ROS generation and extracellular ROS release, with and without stimulation (Fcgamma-receptor and Fusobacterium nucleatum), using luminol and isoluminol chemiluminescence. Assays were performed with and without priming with Escherichia coli lipopolysaccharide (LPS) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Phox gene expression (p22, p47, p67, gp91) was investigated using reverse transcription-polymerase chain reaction (RT-PCR). Neutrophils from patients produced higher mean levels of ROS in all assays. Total generation and extracellular release of ROS by patients' cells were significantly greater than those from controls after FcgammaR-stimulation, with (P = 0.023) and without (P < or = 0.023) priming with GM-CSF. Differences in unstimulated total ROS generation were not significant. By contrast, patients' cells demonstrated greater baseline, extracellular ROS release than those from controls (P = 0.004). This difference was maintained after priming with LPS (P = 0.028) but not GM-CSF (P = 0.217). Phox gene expression was similar in patient and control cells at baseline and stimulation with F. nucleatum (3 h) consistently reduced gp91(PHOX) transcripts. Our data demonstrate that peripheral neutrophils from periodontitis patients exhibit hyper-reactivity following stimulation (Fcgamma-receptor and F. nucleatum) and hyperactivity in terms of excess ROS release in the absence of exogenous stimulation. This hyperactive/-reactive neutrophil phenotype is not associated with elevated phox gene expression.

Adult↗
PubMed2006

Bone marrow cell gene expression and tissue construct assembly using octacalcium phosphate microscaffolds.

Calcium phosphates have been widely used in bone and soft tissue applications and are of considerable interest as scaffold materials due to properties of osteoconduction, resorbability and in some cases osteoinduction. These materials are microcrystalline and as such are processed using sintering, surface coating or cement technologies. However calcium phosphates containing HPO(4)(2-) ions often have layered crystal structures and can form macrocrystals in an aqueous environment at room temperature and pressure. This study aimed to investigate the potential of octacalcium phosphate (OCP) crystals for the attachment, proliferation and differentiation of bone marrow stromal cells and the potential of these cell seeded crystals as 'building blocks' for manufacture of self-supporting macroscale tissue constructs. An inverse relationship between cell number and crystal surface area was found and marrow cells grown on OCP crystals expressed osteocalcin and osteopontin mRNA, markers of osteoblastic differentiation, even in the absence of inductive media additives. Self-supporting crystal tissue macroscale constructs could be fabricated by culturing cell loaded crystals in moulds of the desired shape. Due to the low packing efficiency as a consequence of the high aspect ratio of OCP crystals, this microscaffold approach may offer the potential for ex vivo construction of large volumes of tissue which forms as a physiologically vascularised tissue.

Animals↗
PubMed2005

Comparison of bone marrow cell growth on 2D and 3D alginate hydrogels.

Calcium cross-linked sodium alginate hydrogels have several advantageous features making them potentially suitable as tissue engineering scaffolds and this material has been previously used in many biomedical applications. 3D cell culture systems are often very different from 2D petri dish type cultures. in this study the effect of alginate hydrogel architecture was investigated by comparing rat bone marrow cell proliferation and differentiation on calcium cross linked sodium alginate discs and 1mm internal diameter tubes. It was found that bone marrow cell proliferation was diminished as the concentration of alginate in the 2D hydrogel substrates increased, yet proliferation was extensive on tubular alginate constructs with high alginate contents. Alginate gel thickness was found to be an important parameter in determining cell behaviour and the different geometries did not generate significant alterations in BMC differentiation profiles.

Absorbable Implants↗
PubMed2005

British Orthodontic Society, Chapman Prize Winner 2003. A novel in vitro culture model to investigate the reaction of the dentine-pulp complex to orthodontic force.

OBJECTIVE: To develop a novel mandible slice organ culture model to investigate the effects of externally applied force on the dentine-pulp complex. DESIGN: In vitro organ culture. SETTING: School of Dentistry, Birmingham, UK. MATERIALS AND METHODS: Transverse 2 mm thick sections were cut from the mandibles of five 28-day-old male Wistar rats. Serial sections were used for control and test pairs. Springs made from 0.016-inch and 0.019 x 0.025-inch stainless steel wires were used to apply a 50 g tensile or compressive force, respectively, to test specimens. Control and test specimens were cultured for 5 days in a humidified incubator with 5% CO(2) at 37 degrees C and processed for routine histological investigation. Nine more rats were used to provide control and compression test pairs where the pulps were extirpated after 3 days culture and total RNA isolated for gene expression analysis by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Histology showed the dental and supporting tissues maintained a healthy appearance in the control cultures after culture. Histomorphometric analysis revealed a 20-27% increase in pulp fibroblast density in test specimens compared with controls. Gene expression analyses revealed up-regulation in the test groups of PCNA, c-Myc, Collagen 1alpha, TGF-beta1 and alkaline phosphatase, whilst expression of osteocalcin was reduced. CONCLUSIONS: The results demonstrated that the present organ culture technique provides a valuable in vitro experimental model for studying the effects of externally applied forces. These forces stimulated a cellular response in the pulp chamber characterized by altered gene expression and proliferation of fibroblasts; the latter being unaffected by the nature of the force in terms of compression or tension.

Alkaline Phosphatase↗
PubMed2003

Evaluation of sodium alginate for bone marrow cell tissue engineering.

Sodium alginate has applications as a material for the encapsulation and immobilisation of a variety of cell types for immunoisolatory and biochemical processing applications. It forms a biodegradable gel when crosslinked with calcium ions and it has been exploited in cartilage tissue engineering since chondrocytes do not dedifferentiate when immobilised in it. Despite its attractive properties of degradability, ease of processing and cell immobilisation, there is little work demonstrating the efficacy of alginate gel as a substrate for cell proliferation, except when RGD is modified. In this study we investigated the ability of rat bone marrow cells to proliferate and differentiate on alginates of differing composition and purity. The mechanical properties of the gels were investigated. It was found that high purity and high G-type alginate retained 27% of its initial strength after 12 days in culture and that comparable levels of proliferation were observed on this material and tissue culture plastic. Depending on composition, calcium crosslinked alginate can act as a substrate for rat marrow cell proliferation and has potential for use as 3D degradable scaffold.

Alginates↗
PubMed2001

Mapping of genes and transcribed sequences in a gene rich 400-kb region on human chromosome 11p15.1-->p14.

We have identified a number of transcribed sequences within a 400-kb interval on chromosome 11p15.1--> p14. Six genes and 13 novel transcripts including ESTs, cDNAs and exons have been identified and assigned to this region. Comparison of mRNA sequence with genomic sequence has enabled us to determine the exon/intron structure of four of the genes (NUCB2, PIK3C2A, RPS13 and OR7E14P).

Base Sequence↗
PubMed2001

Cloning and expression analysis of a novel G-protein-coupled receptor selectively expressed on granulocytes.

The migration of neutrophils into sites of acute and chronic inflammation is mediated by chemokines. We used degenerate-primer reverse transcriptase-polymerase chain reaction (RT-PCR) to analyze chemokine receptor expression in neutrophils and identify novel receptors. RNA was isolated from human peripheral blood neutrophils and from neutrophils that had been stimulated for 5 h with granulocyte-macrophage colony-stimulating factor or by coculturing with primary human bronchial epithelial cells. Amplification products were cloned, and clone redundancy was determined. Seven known G-protein-coupled receptors were identified among 38 clones-CCR1, CCR4, CXCR1, CXCR2, CXCR4, HM63, and FPR1-as well as a novel gene, EX33. The full-length EX33 clone was obtained, and an in silico approach was used to identify the putative murine homologue. The EX33 gene encodes a 396-amino-acid protein with limited sequence identity to known receptors. Expression studies of several known chemokine receptors and EX33 revealed that resting neutrophils expressed higher levels of CXCRs and EX33 compared with activated neutrophils. Northern blot experiments revealed that EX33 is expressed mainly in bone marrow, lung, and peripheral blood leukocytes. Using RT-PCR analysis, we showed more abundant expression of EX33 in neutrophils and eosinophils, in comparison with that in T- or B-lymphocytes, indicating cell-specific expression among leukocytes.

Adult↗
PubMed2000

cDNA representational difference analysis of human neutrophils stimulated by GM-CSF.

Neutrophils are the first cell type to migrate out of the vascular space and into the inflammatory site during an acute inflammation. However, in chronic inflammatory diseases, such as chronic obstructive pulmonary disease (COPD), a lack of clearance of neutrophils, imbalance between inflammatory mediators produced by neutrophils and their natural inhibitors make these cells a potential cause of tissue destruction in lung disease. Neutrophilic inflammation is generally characterised by high levels of local expression of activating cytokines (e.g., GM-CSF). Only a few studies have been published so far that have investigated the expression of genes preferentially expressed in activated neutrophils. The isolation of such genes, however, can lead to a better understanding of inflammatory disease and the identification of potential novel therapeutic targets or markers of the disease. We performed representational difference analysis of cDNA, a sensitive PCR-based subtractive enrichment procedure, and isolated 12 genes, 1 EST clone, and 3 sequences not represented in the public databases. Differential expression for 9 of these clones was confirmed by Northern hybridisation. Of the above nine transcripts three were chosen and shown to be up-regulated in neutrophils cocultured with stimulated primary human bronchial epithelial cells using a semiquantitative RT-PCR approach. Among the known genes identified were HM-74, CIS1, Cathepsin C, alpha-enolase, CD44, and the gene Translocation Three Four (TTF), most of them previously not known to be involved in GM-CSF induced neutrophil activation. Along with its tissue and cellular distribution we also derived the complete cDNA sequence and genomic structure of CIS1 using an in silico approach. In addition, we also report the initial characterisation of a novel gene, P1-89 that is primarily expressed in granulocytes and is up-regulated in activated cells. Our results identify several important genes associated with neutrophil activation and can lead to a better understanding of the molecular mechanisms of neutrophilic inflammations.

Amino Acid Sequence↗
PubMed2000

Spinal cord astrocytomas: presentation, management and outcome.

Intramedullary spinal cord astrocytomas are uncommon tumors. They are the most common spinal cord tumor in children and in adults are second only to ependymomas in frequency of occurrence. Low-grade histology predominates with high-grade lesions comprising only ten to fifteen percent of pediatric tumors and a slightly higher proportion in adults. Presenting symptoms typically evolve over months to years with regional back pain the most commonly reported initial complaint. Malignant tumors produce rapid neurological deterioration. MRI is the diagnostic modality of choice: spinal cord astrocytomas are iso- to slightly hypointense on T1, hyperintense on T2 and commonly have associated cysts. They enhance less intensely and are more eccentric than ependymomas. The goals of surgical intervention are to obtain a tissue diagnosis and resect as much tumor as possible without adversely affecting neurological function. Astrocytomas are infiltrating neoplasms and total resection is not generally possible. Somatosensory and motor evoked potential monitoring are routinely used but it is unclear if they improve outcomes. The operating microscope and bipolar cautery are essential surgical tools; the ultrasound and ultrasonic surgical aspirator are useful surgical adjuncts. Laminectomy is performed on adults while laminoplasty is favored for pediatric patients. Outcome for low-grade astrocytomas is less favorable than that of ependymomas with regard to both recurrence and function though many have prolonged survival. There is no correlation of extent of resection and recurrence. Outcome for high-grade tumors is extremely poor; tumor progression is relentless; median survival is thirteen months in children and six months in adults.

Adult↗
PubMed1999

A maternally methylated CpG island in KvLQT1 is associated with an antisense paternal transcript and loss of imprinting in Beckwith-Wiedemann syndrome.

Loss of imprinting at IGF2, generally through an H19-independent mechanism, is associated with a large percentage of patients with the overgrowth and cancer predisposition condition Beckwith-Wiedemann syndrome (BWS). Imprinting control elements are proposed to exist within the KvLQT1 locus, because multiple BWS-associated chromosome rearrangements disrupt this gene. We have identified an evolutionarily conserved, maternally methylated CpG island (KvDMR1) in an intron of the KvLQT1 gene. Among 12 cases of BWS with normal H19 methylation, 5 showed demethylation of KvDMR1 in fibroblast or lymphocyte DNA; whereas, in 4 cases of BWS with H19 hypermethylation, methylation at KvDMRl was normal. Thus, inactivation of H19 and hypomethylation at KvDMR1 (or an associated phenomenon) represent distinct epigenetic anomalies associated with biallelic expression of IGF2. Reverse transcription-PCR analysis of the human and syntenic mouse loci identified the presence of a KvDMR1-associated RNA transcribed exclusively from the paternal allele and in the opposite orientation with respect to the maternally expressed KvLQT1 gene. We propose that KvDMR1 and/or its associated antisense RNA (KvLQT1-AS) represents an additional imprinting control element or center in the human 11p15.5 and mouse distal 7 imprinted domains.

Animals↗
PubMed1999

Cervical spondylotic myelopathy: patterns of neurological deficit and recovery after anterior cervical decompression.

OBJECTIVES: We evaluated the specific pattern of pre- and postoperative neurological signs and symptoms and functional results in patients with cervical spondylotic myelopathy who underwent anterior decompressive operations. Additionally, we sought to determine which findings had predictive value for surgical outcome. METHODS: We retrospectively reviewed the records of 76 patients with cervical spondylotic myelopathy caused by osteophytic ridge or intervertebral disc herniation who underwent anterior cervical decompression and fusion performed by one surgeon. The patients were evaluated postoperatively by office visits and/or telephone interviews. Outcome was assessed by objective neurological examination and scoring with multiple functional rating scales. RESULTS: The most common preoperative symptoms were deterioration of hand use (75%), upper extremity sensory complaints (82.9%), and gait difficulties (80.3%). In the upper extremities, preoperative weakness was most common in the hand intrinsic muscles (56.6%) and triceps (28.9%), and in the lower extremities, preoperative weakness was most common in the iliopsoas (38.8%) and quadriceps (26.3%). In the lower extremities, individual muscle groups had strength improvement rates from 79.1 to 88.1 %; somewhat higher rates, from 81.3 to 90.9%, were observed in the upper extremities. When evaluated by using the Cooper myelopathy scale, lower extremity functional improvement occurred in 46.7% of the patients and upper extremity functional improvement in 75.4%. Overall functional improvement, evaluated by using a modification of the Japanese Orthopedic Association Scale, was noted in 79.7% of the patients who had abnormal scores preoperatively. CONCLUSION: Strength improved at rates of approximately 80 to 90% in individual muscle groups after anterior cervical decompression. However, fewer than half of all patients experienced functional improvement in the lower extremities, a discrepancy that was probably caused by persistent spasticity rather than muscle weakness. Postoperative dysfunction in the upper extremities was caused by residual weakness as well as sensory loss. Recurrent symptomatic spondylosis at unoperated levels was calculated to occur at an incidence of 2% per year.

Adult↗
PubMed1999

Contemporary management of spinal osteomyelitis.

OBJECTIVE: We review the results of treatment of a series of patients with spinal osteomyelitis, to formulate a systematic and comprehensive approach to the management of this disease in light of recent technical and conceptual advances in imaging, spinal biomechanics, and internal fixation. METHODS: We retrospectively reviewed the records for 57 consecutive patients with pyogenic spinal osteomyelitis who were treated between June 1987 and June 1995. Pain and weakness were the most common presenting symptoms. The mean duration of symptoms at the time of diagnosis was 10.6 weeks. Surgical indications included the presence or development of motor deficits with epidural compression and/or localized kyphotic deformities or the failure of medical therapy. RESULTS: Thirty-three patients underwent surgery as their initial treatment. Six additional patients experienced medical therapy failure and received subsequent surgical treatment. Seventeen patients were treated using an anterior approach only, 13 were treated using a posterior approach only, and 9 were treated using a combined anterior and posterior approach. After a minimal follow-up period of 24 months, 93% of the surgically treated patients showed neurological improvement or were neurologically intact, with a mean 16-degree decrease in localized kyphotic deformities and with solid bony fusion and resolution of pain for all patients. CONCLUSION: Early surgical decompression results in rapid improvement of neurological deficits, decreases in kyphotic deformities, and stabilization with bony fusion. The presence of active infection does not preclude the use of internal fixation. Nonsurgical management is indicated for patients with minimal or no neurological deficits and the absence of significant localized kyphotic deformities. However, 25% of patients who were initially treated nonsurgically experienced medical therapy failure and underwent surgical treatment.

Adult↗
PubMed1998

Transcript mapping of the human chromosome 11q12-q13.1 gene-rich region identifies several newly described conserved genes.

Despite the localization of several human diseases to 11q13, the majority of the genes responsible for these disorders have not yet been cloned. Exon amplification and EST mapping were performed using clones derived from an approximately 1.65-Mb P1 artificial chromosome contig encompassing the region that reportedly harbors the gene mutated in the dominantly inherited eye disorder, Best disease. Fifty-eight exons isolated from the region were sequenced, resulting in 41.3% showing weak or no similarity to database sequences. Four exons had exact matches with human ESTs and 2 exons were highly similar to mouse ESTs. The sequence of 1 of these human ESTs was highly similar to that of the rat Rabin3 and mouse Pat-12 genes, which potentially encode Ras-like GTPase binding proteins. Three exon sequences were similar to those of the inner centromere proteins of Gallus gallus and Xenopus laevis, which are mitotic phosphoproteins, and 1 exon sequence had similarity to the epidermal growth factor-like repeat from several proteins. High-resolution mapping of 34 ESTs binned to the 11q12-q13 region by the Human Transcript Mapping Project identified 5 present in the PAC contig, with 1 of these ESTs identifying a human homologue of the rat synaptotagmin VII gene. Database searches identified two overlapping cDNA clones representing almost the entire open reading frame of this human gene and a sequenced cosmid indicating its partial genomic structure. Further database analyses identified another sequenced cosmid from this region that contained both exon-trap and mapped EST sequences. PowerBLAST and GRAIL analysis of this cosmid sequence identified matches with several other ESTs, the previously described FEN1 gene, and a novel evolutionarily conserved gene. These experiments identify candidate genes for disorders that map to this region and indicate that this is a gene-rich region of the human genome.

Amino Acid Sequence↗
PubMed1998

Nibrin, a novel DNA double-strand break repair protein, is mutated in Nijmegen breakage syndrome.

Nijmegen breakage syndrome (NBS) is an autosomal recessive chromosomal instability syndrome characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition. Cells from NBS patients are hypersensitive to ionizing radiation with cytogenetic features indistinguishable from ataxia telangiectasia. We describe the positional cloning of a gene encoding a novel protein, nibrin. It contains two modules found in cell cycle checkpoint proteins, a forkhead-associated domain adjacent to a breast cancer carboxy-terminal domain. A truncating 5 bp deletion was identified in the majority of NBS patients, carrying a conserved marker haplotype. Five further truncating mutations were identified in patients with other distinct haplotypes. The domains found in nibrin and the NBS phenotype suggest that this disorder is caused by defective responses to DNA double-strand breaks.

Amino Acid Sequence↗
PubMed1998

Divergently transcribed overlapping genes expressed in liver and kidney and located in the 11p15.5 imprinted domain.

Human chromosomal band 11p15.5 has been shown to contain genes involved in the development of several pediatric and adult tumors and in Beckwith-Wiedemann syndrome (BWS). Overlapping P1 artificial chromosome clones from this region have been used as templates for genomic sequencing in an effort to identify candidate genes for these disorders. PowerBLAST identified several matches with expressed sequence tags (ESTs) from fetal brain and liver cDNA libraries. Northern blot analysis indicated that two of the genes identified by these ESTs encode transcripts of 1-1.5 kb with predominant expression in fetal and adult liver and kidney. With RT-PCR and RACE, full-length transcripts were isolated for these two genes, with the largest open reading frames encoding putative proteins of 253 and 424 amino acids. Database comparison of the predicted amino acid sequence of the larger transcript indicated homology to integral membrane organic cation transporters; hence, we designate this gene ORCTL2 (organic cation transporter-like 2). An expressed sequence polymorphism provided evidence that the ORCTL2 gene exhibits "leaky" imprinting in both human fetal kidney and human fetal liver. The mouse orthologue (Orctl2) was identified, and a similar polymorphism was used to demonstrate maternal-specific expression of this gene in fetal liver from interspecific F1 mice. The predicted protein of the smaller gene showed no significant similarity in the database. Northern and RACE analyses suggest that this gene may have multiple transcription start sites. Determination of the genomic structure in humans indicated that the 5'-end of this transcript overlaps in divergent orientation with the first two exons of ORCTL2, suggesting a possible role for antisense regulation of one gene by the other. We, therefore, provisionally name this second transcript ORCTL2S (ORCTL2-antisense). The expression patterns of these genes and the imprinted expression of ORCTL2 are suggestive of a possible role in the development of Wilms tumor (WT) and hepatoblastoma. Although SSCP analysis of 62 WT samples and 10 BWS patients did not result in the identification of any mutations in ORCTL2 or ORCTL2S, it will be important to examine their expression pattern in tumors and BWS patients, since epigenetic alteration at these loci may play a role in the etiology of these diseases.

Amino Acid Sequence↗
PubMed1998

A gene map of the Best's vitelliform macular dystrophy region in chromosome 11q12-q13.1.

Best's vitelliform macular dystrophy is an autosomal dominant disorder of unknown causes. To identify the underlying gene defect the disease locus has been mapped to an approximately 1.4-Mb region on chromosome 11q12-q13.1. As a prerequisite for its positional cloning we have assembled a high coverage PAC contig of the candidate region. Here, we report the construction of a primary transcript map that places a total of 19 genes within the Best's disease region. This includes 14 transcripts of as yet unknown function obtained by EST mapping and/or cDNA selection and five genes mapped previously to the interval (CD5, PGA, DDB1, FEN1, and FTH1). Northern blot analyses were performed to determine the expression profiles in various human tissues. At least three genes appear to be good candidates for Best's disease based on their abundant expression in retina or retinal pigment epithelium. Additional information on the functional properties of these genes, as well as mutation analyses in Best's disease patients, have to await their further characterization. [The GenBank/EMBL accession numbers and details of the isolation, localization, and characterization of ESTs and selected cDNAs are available as online supplements in Online Tables 1-3 at http://www.genome.org.]

Calcium-Binding Proteins↗