Search PubMed⌕ Search

Biomedical subjects

J Cummins

Publications and source records attributed to J Cummins.

At least 19 recordsLinked to original sources
PubMed2005

Regeneration of dystrophin-expressing myocytes in the mdx heart by skeletal muscle stem cells.

Cell transplantation holds promise as a potential treatment for cardiac dysfunction. Our group has isolated populations of murine skeletal muscle-derived stem cells (MDSCs) that exhibit stem cell-like properties. Here, we investigated the fate of MDSCs after transplantation into the hearts of dystrophin-deficient mdx mice, which model Duchenne muscular dystrophy (DMD). Transplanted MDSCs generated large grafts consisting primarily of numerous dystrophin-positive myocytes and, to a lesser degree, dystrophin-negative non-myocytes that expressed an endothelial phenotype. Most of the dystrophin-positive myocytes expressed a skeletal muscle phenotype and did not express a cardiac phenotype. However, some donor myocytes, located at the graft-host myocardium border, were observed to express cardiac-specific markers. More than half of these donor cells that exhibited a cardiac phenotype still maintained a skeletal muscle phenotype, demonstrating a hybrid state. Sex-mismatched donors and hosts revealed that many donor-derived cells that acquired a cardiac phenotype did so through fusion with host cardiomyocytes. Connexin43 gap junctions were not expressed by donor-derived myocytes in the graft. Scar tissue formation in the border region may inhibit the fusion and gap junction connections between donor and host cells. This study demonstrates that MDSC transplantation warrants further investigation as a potential therapy for cardiac dysfunction in DMD.

Animals↗
PubMed2003

Muscle cell-mediated gene delivery to the rotator cuff.

Rotator cuff lesions are one of the most common causes of upper extremity disability. Surgical therapy addresses mostly the extrinsic etiology, but not intrinsic factors such as aging, structural changes, low vascularity, and inflammatory processes. In this study, genetically engineered, highly purified muscle-derived cells (MDCs) were characterized and injected into the supraspinatus tendons of nude rats. The injected cells were monitored for 3 weeks. In vitro, the engineered, highly purified MDCs do not express vimentin; 98% of them are positive for the beta-galactosidase marker gene, and 99% hybridize with the specific pancentromeric mouse probe. beta-Galactosidase marker gene expression of the injected cells was detected up to 21 days. From day 7 after injection, the cell nuclei became spindle shaped, cells were integrated into the tendon collagen bundles, and the cells showed differentiation into vimentin-expressing fibroblastic cells. The results indicate that the rotator cuff tendon matrix and its original cellular components modulated the injected MDCs toward a fibroblastic phenotype. The compatibility and ability of MDCs to differentiate into other cell lineages, such as fibroblasts, might have high potential utility in tissue-engineering applications for tendon healing. This approach facilitates the application of muscle-derived progenitor cells and ex vivo gene therapy for the treatment of rotator cuff lesions.

Animals↗
PubMed2001

ASCOT: a comprehensive clinical database for gastro-oesophageal cancer surgery.

We report the development of a multicentre prospective database for gastro-oesophageal cancer surgery. The ASCOT project aims to collect detailed prospective data on co-morbidity, surgery, stage and outcome in a large cohort of patients from a wide variety of hospitals in the UK. We describe the rationale for the initiative, the process of defining the dataset, the database software and structure, the system for data recording and retrieval and the operating rules of the ASCOT co-operative group. Thirty Trusts are currently submitting data, and the first 1000 cases have now been entered. A first annual report has been produced, showing anonymized comparative figures for patient characteristics and outcomes of interest, and a second is due shortly. The collection of detailed comparable data, including co-morbidity evaluation, on a large scale is likely to prove valuable for unit specialist accreditation, surgeon re-validation, audit and research.

Cohort Studies↗
PubMed2001

Mitochondrial DNA and the Y chromosome: parallels and paradoxes.

Both mitochondrial DNA (mtDNA) and the Y chromosome have been used extensively by molecular paleoanthropologists in attempts to reconstruct human lineages. Both are inherited in a haploid manner: mtDNA through the female and the Y through the male. For mtDNA, maternal inheritance is ensured by a species-specific mechanism of proteolysis of the sperm midpiece in early embryogenesis, based on ubiquitination of the mitochondria during spermiogenesis. Both genomes are thought to lack recombination and are thus liable to high rates of neutral mutation. For the human Y chromosome, it is now clear that there has been selection on genes controlling spermatogenesis, resulting in differential long-term reproductive success. This is corroborated from studies of genealogies and hunting-gathering societies, although these lack the rigour provided by the modern molecular markers of inheritance. Selection is made more complicated by a concentration of genes controlling secondary sexual characteristics on the X chromosome. Likewise, mtDNA affects the bioenergetics of gametogenesis and embryo development, as well as longevity, disease and the aging process. Both Y chromosome and mitochondrial haplotypes show significant associations with patterns of male infertility that could distort their use for phylogenetic reconstruction. Moreover, the molecular analysis of mtDNA is complicated by the presence of numerous nuclear mitochondrial pseudogenes (Numts) that can be erroneously amplified by molecular techniques such as PCR. This review examines some of these complex interactions and suggests that some of the more contentious issues in understanding human evolution may be resolved by considering the biology of these genetic markers.

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

Osteoprogenitor cells within skeletal muscle.

The formation of ectopic bone within skeletal muscle is a widely observed phenomenon. However, the source of the osteoprogenitor cells responsible for ectopic bone formation remains unknown. This study was designed to test for osteogenic differentiation among cells isolated from skeletal muscle tissue. Different subpopulations of cells derived from an adult mouse skeletal muscle were tested for induction of alkaline phosphatase activity after exposure to bone morphogenetic protein-2 in vitro. A responsive subpopulation was identified, transduced with a retrovirus encoding for beta-galactosidase (Rv-lacZ) and an adenoviral construct encoding for one bone morphogenetic protein-2, and injected into the hindlimb of immune compromised (severe combined immunodeficient, or SCID) mice. The injected cells appeared to actively participate in the ectopic bone formation. The existence of lacZ-positive muscle-derived cells colocalized with osteocalcin-producing cells within lacunae of newly formed bone matrix suggests osteoblast and osteocyte differentiation. Although a specific cell was not isolated, these data support the contentions that osteoprogenitor cells reside within skeletal muscle and that muscle may represent a source other than bone marrow for the harvest of these cells.

Alkaline Phosphatase↗
PubMed1999

Oral use of interferon-alpha stimulates ISG-15 transcription and production by human buccal epithelial cells.

ISG-15 is a 15-kDa protein encoded by an interferon (IFN)-stimulated gene (ISG), which is transcriptionally regulated by IFN-alpha and IFN-beta. Considered as part of the cytokine network, ISG-15 has the potential to amplify the immunomodulatory effects of these IFNs by enhancing IFN-gamma production, natural killer cell proliferation, and lymphokine-alphactivated killer cell cytotoxicity. To understand better the mechanism(s) of action of orally administered IFN-alpha, we have studied the effect of IFN-alpha on ISG-15 gene expression by human buccal epithelial cells (BEC). For in vitro studies, ISG-15 mRNA and protein levels were measured in BEC incubated for 0.5, 2, and 9 h with 100 or 1,000 IU/ml of human lymphoblastoid IFN-alpha. For in vivo studies, ISG-15 mRNA was measured in BEC samples collected at baseline, and 0.5, 2, and 9 h after 5-20 min of oral rinsing with 10 ml of IFN-alpha (1,000 IU/ml). ISG-15 mRNA was measured by reverse transcriptase polymerase chain reaction (RT-PCR), and ISG-15 protein production by Western Blot analysis. IFN-alpha augmented BEC ISG-15 gene expression in a concentration dependent manner both in vivo and in vitro. We conclude that orally administered IFN-alpha exerts its immunomodulatory effects in humans in part by upregulating the production of ISG-15 by BEC, thereby enhancing the immune reactivity of mucosa-associated lymphocytes.

Adjuvants, Immunologic↗
PubMed1998

Interferon-alpha inhibits the emergence of cellular stress response-dependent morbillivirus large plaque variants.

Cellular levels of heat shock proteins (HSPs) are elevated in response to physiologic states accompanying acute virus infection (e.g. fever). The objective of the present work was to define the antiviral effect of purified human lymphoblastoid IFN in the presence of HSP over-expression. For this purpose, canine distemper virus (CDV) was used since the response of CDV transcription and persistent infection phenotype to elevated HSP is characterized. First, the effect of elevated HSP on CDV lytic infection phenotype in Vero and CV1 cells was defined, and results extended to the closely related measles virus (MV). Cells expressing elevated levels of the major inducible 70-kDa HSP (hsp72) supported the emergence of large plaque variants of both CDV and MV from small plaque purified inocula. IFN treatment concurrent with infection caused a dosage-dependent reduction in the expression of large plaque variants without affecting hsp72 levels or total plaque number. In contrast to the stress response-induced large plaque variant, small plaques were resistant to the antiviral effects of IFN. These data demonstrate the ability of IFN to selectively abrogate the pro-viral effects of HSP over-expression, inhibiting the formation of a plaque phenotype that is correlated to enhanced virulence in animal models of morbillivirus encephalitis.

Animals↗
PubMed1998

Study IV: concurrent validity of the DSM-IV revised Children's Interview for Psychiatric Syndromes (ChIPS).

OBJECTIVE: To determine validity of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (DSM-IV) revised Children's Interview for Psychiatric Syndromes (ChIPS) in inpatient children and adolescents. METHOD: Participants were 47 psychiatric inpatients 6-12 (n = 23) and 12 to 18 years of age (n = 24). ChIPS was administered to all participants. The Diagnostic Interview for Children and Adolescents-Revised-Child Version (DICA-R-C) was administered to 40 participants. Discharge diagnoses were recorded for all participants. Kappas, low base rate kappas, and percentage agreement were used to assess diagnostic agreement between sources for 18 disorders. RESULTS: ChIPS/DICA-R-C kappas could not be calculated for two disorders because of 100% agreement on their absence. Fourteen of 16 kappas were significant (p < 0.05). The remaining 2 of 16 disorders had 98% agreement (kappax = 0.494, p < 0.157). When ChIPS results were compared with discharge diagnoses, sensitivity for each disorder averaged 70%, whereas specificity averaged 84%. When disagreements occurred between all three sources, ChIPS was somewhat more likely than DICA-R-C to agree with discharge diagnoses (27% versus 22%). Analysis were repeated for children and adolescents, then for boys and girls. Boys and children had fewer significant ChIPS and DICA-R-C kappa coefficients compared with girls and adolescents; this appeared to be related to the fewer number of diagnoses they endorsed. ChIPS/clinician agreement was similar for boys and girls as well as for children and adolescents. Administration time was less for ChIPS than for DICA-R-C (p < 0.08). CONCLUSION: Psychometric properties of the DSM-IV revised ChIPS compare favorably with that of other structured interviews. ChIPS appears to work well for adolescents as well as children.

Adolescent↗
PubMed1998

Mitochondrial DNA in mammalian reproduction.

Mitochondrial DNA (mtDNA) forms a semi-autonomous asexually reproducing genome in eukaryotic organisms. It plays an essential role in the life cycle through the control of energy production, by the inherently dangerous process of oxidative phosphorylation. The asymmetric nature of its inheritance--almost exclusively through the female--imposes different evolutionary constraints on males and females, and may lie at the heart of anisogamy. This review examines the implications of recent findings on the biology of mtDNA for reproduction and inheritance in mammals.

Animals↗
PubMed1997

Mapping of the human P84 gene to the subtelomeric region of chromosome 20p.

P84 is a novel neural adhesion molecule that may play an important role in synaptogenesis. We have recently cloned a murine cDNA encoding the P84 adhesion molecule. The human homologue of P84 has previously been isolated (by others) as a brain specific cDNA containing CCA repeats. We have mapped the human P84 gene to the subtelomeric region of chromosome 20p (20p13) by FISH. In addition, we have been able to place P84 onto the high resolution physical map of the human genome by utilizing the Unigene database. P84 maps to several YAC clones, between STS markers IB255 and WI-9632, and very close to the polymorphic marker D20S199, in an interval of less than 1 Mb on 20p13. P84 is a strong candidate gene for neurological disorders which map into this region.

Animals↗
PubMed1996

Chromosomal mapping of the human M6 genes.

M6 is a neuronal membrane glycoprotein that may have an important role in neural development. This molecule was initially defined by a monoclonal antibody that affected the survival of cultured cerebellar neurons and the outgrowth of neurites. The nature of the antigen was discovered by expression cDNA cloning using this monoclonal antibody. Two distinct murine M6 cDNAs (designated M6a and M6b) whose deduced amino acid sequences were remarkably similar to that of the myelin proteolipid protein were previously isolated. We have isolated partial human cDNA and genomic clones encoding M6a and M6b and have characterized them by restriction mapping, Southern hybridization with cDNA probes, and sequence analysis. We have localized these genes within the human genome by FISH (fluorescence in situ hybridization). The human M6a gene is located at 4q34, and the M6b gene is located at Xp22.2. A number of human neurological disorders have been mapped to the Xp22 region, including Aicardi syndrome (MIM 304050), Rett syndrome (MIM 312750), X-linked Charcot-Marie-Tooth neuropathy (MIM 302801), and X-linked mental retardation syndromes (MRX1, MIM 309530). This raises the possibility that a defect in the M6b gene is responsible for one of these neurological disorders.

Amino Acid Sequence↗
PubMed1996

Kallikrein gene expression in human pituitary tissues.

OBJECTIVE: The glandular kallikreins are a family of enzymes involved in the post-translational processing of polypeptides. Three family members have been characterized in the human: glandular kallikrein (KLK1) and two genes expressed in the prostate, KLK2 or hGK1 and KLK3 or prostate specific antigen (PSA). Both kallikrein immunoreactivity and KLK1 mRNA have been detected in the rat anterior pituitary and oestrogen induced prolactinomas. Immunoreactive kallikrein has also been reported in prolactin secreting pituitary tumours in humans. In this study we wished to determine whether KLK1 and/or other KLK genes were expressed in human pituitary tumours. DESIGN AND PATIENTS: Retrospective analysis of KLK gene expression in pituitary tissue obtained at surgery from 11 patients with a range of pituitary syndromes, 10 of which were tumour induced and included four prolactinomas. Three normal pituitaries, obtained at necropsy, were also analysed. MEASUREMENTS: Pituitary total RNA was subjected to both Northern blot analysis, with KLK1 and KLK2 cDNA probes, and KLK-specific reverse transcriptase -- polymerase chain reaction (RT-PCR). RESULTS: No KLK1 gene expression was detected on Northern blot analysis although expression of PRL, GH and pro-opiomelanocortin (POMC) was variously detected. KLK RT-PCR coupled with Southern blot analysis using oligonucleotide probes specific for each of the three KLK genes was positive in many tumours but with varying levels and differential expression. Overall, KLK1 was the most abundant with KLK3 the least. The identity of KLK1 and KLK2 was confirmed by sequencing the PCR products. There was no obvious correlation between KLK1 and hormone gene expression; KLK1 was present in PRL positive and negative tumours and in normal pituitary tissue. CONCLUSIONS: We have demonstrated a low level of expression of KLK1 as well as KLK2 and KLK3 in the human pituitary. The expression of KLK2 and KLK3 in the pituitary is a novel finding. The lack of correlation between PRL and KLK1 gene expression is an unexpected finding suggesting that the interaction between these factors may be more complex in the human pituitary than in the rodent model.

Adolescent↗
PubMed1995

Corticosteroid injection therapy for overuse injuries.

Local corticosteroid injection therapy may be considered for many conditions commonly treated by the primary care physician. Chronic overuse and flawed biomechanics may lead to inflammation in areas easily accessible to injected local corticosteroids, including bursae, tendon sheaths and joints. It is generally preferable to mix the steroid preparation with an anesthetic agent to minimize the injection pain, provide immediate symptom relief and confirm the diagnosis. Local complications of corticosteroid injection include tendon and ligament weakening, bacterial infections of joints and related structures, and subcutaneous tissue atrophy. Systemic complications are rare but reportedly include hyperglycemia and adrenal axis suppression.

Adrenal Cortex Hormones↗