Biomedical subjects

William J Murphy

Publications and source records attributed to William J Murphy.

At least 37 records · Page 2Linked to original sources

PubMed2005

A molecular phylogeny for bats illuminates biogeography and the fossil record.

Bats make up more than 20% of extant mammals, yet their evolutionary history is largely unknown because of a limited fossil record and conflicting or incomplete phylogenies. Here, we present a highly resolved molecular phylogeny for all extant bat families. Our results support the hypothesis that megabats are nested among four major microbat lineages, which originated in the early Eocene [52 to 50 million years ago (Mya)], coincident with a significant global rise in temperature, increase in plant diversity and abundance, and the zenith of Tertiary insect diversity. Our data suggest that bats originated in Laurasia, possibly in North America, and that three of the major microbat lineages are Laurasian in origin, whereas the fourth is Gondwanan. Combining principles of ghost lineage analysis with molecular divergence dates, we estimate that the bat fossil record underestimates (unrepresented basal branch length, UBBL) first occurrences by, on average, 73% and that the sum of missing fossil history is 61%.

Africa↗

PubMed2005

Novel tumor necrosis factor-knockout mice that lack Peyer's patches.

We generated a novel tumor necrosis factor (TNF) null mutation using Cre-loxP technology. Mice homozygous for this mutation differ from their "conventional" counterparts; in particular, they completely lack Peyer's patches (PP) but retain all lymph nodes. Our analysis of these novel TNF-knockout mice supports the previously disputed notion of the involvement of TNF-TNFR1 signaling in PP organogenesis. Availability of TNF-knockout strains both with and without PP enables more definitive studies concerning the roles of TNF and PP in various immune functions and disease conditions. Here, we report that systemic ablation of TNF, but not the presence of PP per se, is critical for protection against intestinal Listeria infection in mice.

Animals↗

PubMed2005

Lack of correlation between an assay used to determine early marrow allograft rejection and long-term chimerism after murine allogeneic bone marrow transplantation: effects of marrow dose.

The acute rejection of bone marrow (BM) allografts by host effectors can occur within a short period after BM transplantation (BMT) in lethally irradiated mice. Common assays used to ascertain engraftment/resistance involve measuring the growth of granulocyte/monocyte progenitors (colony-forming unit-granulocyte-macrophage) in vitro or splenocyte proliferation assessed by radioisotope incorporation in vivo 5 to 8 days after BMT. However, the correlation of the long-term outcome of BMT with the kinetics of recovery by using the dose of allogeneic BM cells (BMCs) that leads to early rejection as determined by the in vitro assessment has not been extensively studied. Thus, to investigate whether the early rejection of donor BMCs is an indication of a long-term engraftment failure, C57BL/6 (H2b) mice were lethally irradiated and transplanted with various doses of BALB/c (H2d) BMCs. The short-term engraftment of donor precursors (colony-forming unit-granulocyte-macrophage), the kinetics of hematopoietic cell recovery, the extent of donor chimerism, and the proportion of the recipients with long-term survival were determined. The results show that the kinetics and extent of hematopoietic cell recovery were significantly delayed in mice receiving limiting doses of BMCs that were rejected or severely resisted at day 8 after BMT. However, a proportion of these mice survived up to 98 days after BMT with mixed chimerism or donor chimerism. This study demonstrates that early rejection of BM precursors, as assessed by measurement of myeloid progenitors in the spleen after BMT, does not always correlate with the long-term outcome of the marrow allograft and that significant variability is inherent in the extent of chimerism when threshold amounts of BMCs are used.

Animals↗

PubMed2005

Serum-dependent potentiation of lipopolysaccharide-induced nitric oxide production is mediated by the events after the transcription of inducible type of nitric oxide synthase.

The mechanism of serum-dependent potentiation of lipopolysaccharide (LPS)-induced nitric oxide (NO) production was studied by incubating mouse macrophage cell line, RAW 264.7, in the presence of fetal bovine serum (FBS). The addition of FBS definitely enhanced LPS-induced NO production through augmented expression of inducible type NO synthase (iNOS) mRNA and protein. However, nuclear run-on analysis demonstrated only marginal enhancement in the rate of LPS-induced iNOS gene transcription in the presence of FBS. Further, there was no significant difference in the luciferase reporter gene activity linked to the iNOS promoter-enhancer gene in response to LPS between the presence and absence of FBS. FBS-dependent enhancement did not appear to involve the initial step for triggering iNOS transcription in LPS-induced NO production. Rather, FBS was suggested to affect the accumulation and stabilization of iNOS mRNA leading to iNOS protein and NO production by some post-transcriptional regulatory mechanism.

Animals↗

PubMed2005

A rhesus macaque radiation hybrid map and comparative analysis with the human genome.

The genomes of nonhuman primates are powerful references for better understanding the recent evolution of the human genome. Here we compare the order of 802 genomic markers mapped in a rhesus macaque (Macaca mulatta) radiation hybrid panel with the human genome, allowing for nearly complete cross-reference to the human genome at an average resolution of 3.5 Mb. At least 23 large-scale chromosomal rearrangements, mostly inversions, are needed to explain the changes in marker order between human and macaque. Analysis of the breakpoints flanking inverted chromosomal segments and estimation of their duplication divergence dates provide additional evidence implicating segmental duplications as a major mechanism of chromosomal rearrangement in recent primate evolution.

Animals↗

PubMed2005

Insertional polymorphisms of endogenous feline leukemia viruses.

The number, chromosomal distribution, and insertional polymorphisms of endogenous feline leukemia viruses (enFeLVs) were determined in four domestic cats (Burmese, Egyptian Mau, Persian, and nonbreed) using fluorescent in situ hybridization and radiation hybrid mapping. Twenty-nine distinct enFeLV loci were detected across 12 of the 18 autosomes. Each cat carried enFeLV at only 9 to 16 of the loci, and many loci were heterozygous for presence of the provirus. Thus, an average of 19 autosomal copies of enFeLV were present per cat diploid genome. Only five of the autosomal enFeLV sites were present in all four cats, and at only one autosomal locus, B4q15, was enFeLV present in both homologues of all four cats. A single enFeLV occurred in the X chromosome of the Burmese cat, while three to five enFeLV proviruses occurred in each Y chromosome. The X chromosome and nine autosomal enFeLV loci were telomeric, suggesting that ectopic recombination between nonhomologous subtelomeres may contribute to enFeLV distribution. Since endogenous FeLVs may affect the infectiousness or pathogenicity of exogenous FeLVs, genomic variation in enFeLVs represents a candidate for genetic influences on FeLV leukemogenesis in cats.

Animals↗

PubMed2005

The proteasome inhibitor bortezomib (Velcade) sensitizes some human tumor cells to Apo2L/TRAIL-mediated apoptosis.

On testing a panel of different human cancer cell lines, we observed that the proteasome inhibitor bortezomib could dramatically sensitize some lines to the apoptotic effects of Apo2L/TRAIL. Certain renal, colon, or breast tumor cell lines were dramatically sensitized, whereas other tumor lines from the same tissue of origin remained resistant. This sensitization did not correlate with either the p53 status of the individual tumor cell lines or their intrinsic sensitivity to Apo2L/TRAIL. Colon cancer cell lines lacking p53 or Bax were sensitized by bortezomib, suggesting that neither p53 nor Bax levels were crucial for sensitization. Although the molecular basis of bortezomib sensitization of tumor cells to Apo2L/TRAIL remains to be determined, this combination can have an enhanced apoptotic effect over either agent alone for certain human cancer cells.

Antineoplastic Agents↗

PubMed2004

The feline major histocompatibility complex is rearranged by an inversion with a breakpoint in the distal class I region.

In order to determine the genomic organization of the major histocompatibility complex (MHC) of the domestic cat (Felis catus), DNA probes for 61 markers were designed from human MHC reference sequences and used to construct feline MHC BAC contig map spanning ARE1 in the class II region to the olfactory receptor complex in the extended class I region. Selected BAC clones were then used to identify feline-specific probes for the three regions of the mammalian MHC (class II-class III-class I) for radiation hybrid mapping and fluorescent in situ hybridization to refine the organization of the domestic cat MHC. The results not only confirmed that the p-arm of domestic cat B2 is inverted relative to human Chromosome 6, but also demonstrated that one inversion breakpoint localized to the distal segment of the MHC class I between TRIM39 and TRIM26. The inversion thus disjoined the approximately 2.85 Mb of MHC containing class II-class III-class I (proximal region) from the approximately 0.50 Mb of MHC class I/extended class I region, such that TRIM39 is adjacent to the Chromosome B2 centromere and TRIM26 is adjacent to the B2 telomere in the domestic cat.

Animals↗

PubMed2004

Alpha phenyl-tert-butyl nitrone (PBN) protects syngeneic marrow transplant recipients from the lethal cytokine syndrome occurring after agonistic CD40 antibody administration.

Administration of agonistic monoclonal antibodies or recombinant cytokines is a potential approach to enhance antitumor immunity in bone marrow (BM) transplant recipients, but is complicated by toxicity due to proinflammatory cytokine-mediated vital organ damage. We used a murine syngeneic bone marrow transplant (BMT) model, in which administration of anti-CD40 antibody early after BMT results in overproduction of interleukin-12 (IL-12) and interferon-gamma (IFN-gamma), and lethal gut toxicity to examine the protective effect of the spin trap inhibitor, alpha phenyl-tert-butyl nitrone (PBN). Administration of PBN protected transplant recipients from mortality by significantly attenuating gut toxicity, but did not effect a reduction in the levels of proinflammatory cytokines (IL-12, IFN-gamma, tumor necrosis factor alpha [TNF-alpha], or nitrate/nitrite). Moreover, PBN did not compromise anti-CD40 antibody-mediated antitumor effects in a nontransplantation lymphoma model. Collectively, these data suggest that PBN administration may represent a novel approach for reduction of toxicity without compromise of antitumor effects resulting from administration of therapeutic antibodies in both transplantation and nontransplantation settings.

Animals↗

PubMed2004

Mesozoic origin for West Indian insectivores.

The highly endangered solenodons, endemic to Cuba (Solenodon cubanus) and Hispaniola (S. paradoxus), comprise the only two surviving species of West Indian insectivores. Combined gene sequences (13.9 kilobases) from S. paradoxus established that solenodons diverged from other eulipotyphlan insectivores 76 million years ago in the Cretaceous period, which is consistent with vicariance, though also compatible with dispersal. A sequence of 1.6 kilobases of mitochondrial DNA from S. cubanus indicated a deep divergence of 25 million years versus the congeneric S. paradoxus, which is consistent with vicariant origins as tectonic forces separated Cuba and Hispaniola. Efforts to prevent extinction of the two surviving solenodon species would conserve an entire lineage as old or older than many mammalian orders.

Animals↗

PubMed2004

Inhibition of acute graft-versus-host disease with retention of graft-versus-tumor effects by the proteasome inhibitor bortezomib.

Graft-versus-host disease (GVHD) represents a major hurdle impeding the efficacy of allogeneic bone marrow transplantation (BMT). Bortezomib is a proteasome inhibitor that was recently approved for treatment of myeloma. We found that bortezomib potently inhibited in vitro mixed lymphocyte responses and promoted the apoptosis of alloreactive T cells. Bortezomib given at the time of allogeneic BMT in mice resulted in significant protection from acute GVHD. Reductions in GVHD-associated parameters and biological evidence of proteasome inhibition were observed with this regimen but with no adverse effects on long-term donor reconstitution. Assessment of graft-versus-tumor responses in advanced leukemia-bearing mice demonstrated that only the combination of allogeneic BMT and T cells with bortezomib promoted significant increases in survival. Increased cytotoxic T cell killing of the tumor was also observed. Thus, the combination of proteasome inhibition with selective immune attack can markedly increase the efficacy of BMT in cancer.

Acute Disease↗

PubMed2004

mAbs to Bacillus anthracis capsular antigen for immunoprotection in anthrax and detection of antigenemia.

Bacillus anthracis is surrounded by an antiphagocytic polypeptide capsule composed of poly gamma-D-glutamic acid (gammaDPGA). gammaDPGA has been identified recently as a potential target for vaccine development. Studies of the role of gammaDPGA in disease have been hampered by the poor Ab response to this antigen and the lack of immunochemical reagents. As a consequence, neither the extent of gammaDPGA production during anthrax nor the protective activity of gammaDPGA Abs in inhalation anthrax are known. Here we report production of IgG Abs to gammaDPGA in mice following an immunization regimen using gammaDPGA in combination with agonist mAbs to CD40. mAbs were produced that are specific for gammaDPGA. Passive immunization with gammaDPGA mAbs protected >90% of mice in a pulmonary model of anthrax that was lethal in control mice (P < 0.0001). Use of gammaDPGA mAb in an antigen detection immunoassay found that the appearance of gammaDPGA in serum coincided with the emergence of bacteremia. These studies identify CD40 stimulation as a means for production of Ab and generation of mAbs against a weakly immunogenic antigen and demonstrate that the capsule is an effective target for immunoprotection and for antigen detection in the diagnosis of anthrax.

Animals↗

PubMed2004

Dissociation of NKT stimulation, cytokine induction, and NK activation in vivo by the use of distinct TCR-binding ceramides.

NKT and NK cells are important immune regulatory cells. The only efficient means to selectively stimulate NKT cells in vivo is alpha-galactosylceramide (alphaGalCer). However, alphaGalCer effectively stimulates and then diminishes the number of detectable NKT cells. It also exhibits a potent, indirect ability to activate NK cells. We have now discovered another ceramide compound, beta-galactosylceramide (betaGalCer) (C12), that efficiently diminishes the number of detectable mouse NKT cells in vivo without inducing significant cytokine expression or activation of NK cells. Binding studies using CD1d tetramers loaded with betaGalCer (C12) demonstrated significant but lower intensity binding to NKT cells when compared with alphaGalCer, but both ceramides were equally efficient in reducing the number of NKT cells. However, betaGalCer (C12), in contrast to alphaGalCer, failed to increase NK cell size, number, and cytolytic activity. Also in contrast to alphaGalCer, betaGalCer (C12) is a poor inducer of IFN-gamma, TNF-alpha, GM-CSF, and IL-4 gene expression. These qualitative differences in NKT perturbation/NK activation have important implications for delineating the unique in vivo roles of NKT vs NK cells. Thus, alphaGalCer (which triggers NKT cells and activates NK cells) efficiently increases the resistance to allogeneic bone marrow transplantation while betaGalCer (C12) (which triggers NKT cells but does not activate NK cells) fails to enhance bone marrow graft rejection. Our results show betaGalCer (C12) can effectively discriminate between NKT- and NK-mediated responses in vivo. These results indicate the use of different TCR-binding ceramides can provide a unique approach for understanding the intricate immunoregulatory contributions of these two cell types.

Animals↗

PubMed2004

Effects of organ-specific loss of insulin-like growth factor-I production on murine hematopoiesis.

To determine whether circulating insulin-like growth factor (IGF)-I has a role in hematopoiesis, we examined hematologic parameters in mice with markedly reduced serum levels resulting from a liver-specific inactivation of the IGF-I gene. These mice have normal postnatal growth and development, suggesting that local production of IGF-I can maintain anabolic effects. Liver-specific IGF-I-deficient (LID) mice were compared with control littermates with regard to hematopoietic parameters. Spleen cellularity was decreased in the LID mice compared with control mice. Spleen myeloid progenitors, as determined by colony-forming units-granulocyte/monocyte (CFU-GM) and colony-forming units-high proliferative potential (CFU-HPP), were significantly decreased in the LID mice. Immune parameters, as indicated by the absolute number of B and T cells, did not significantly differ between the knockout and control mice. In contrast to the decreased cellularity and myelopoiesis in the spleen, bone marrow cellularity was not different between the 2 groups, but the total femoral content of CFU-GM and CFU-HPP was significantly increased in the LID mice. The decrease in splenic myelopoiesis was not due to the inability of progenitors to exit the bone marrow, because CFU-GM and burst-forming units-erythroid were significantly increased in the blood of LID mice compared with normal littermates. Administration of exogenous IGF-I to the LID mice for 4 days partially restored myelopoietic parameters in the spleen. Liver production of IGF-I and, therefore, normal serum levels of this hormone, although not necessary for general organ growth and development, seems necessary for survival or transition of myeloid progenitors into the spleen.

Animals↗

PubMed2004

Tumor regression by anti-CD40 and interleukin-2: role of CD40 in hematopoietic cells and organ-specific effects.

CD40 stimulation can synergize with interleukin (IL)-2 for antitumor responses against mouse metastatic renal cell carcinomas, with coincident increases in tumor-specific CD8+ T-cell responses and dendritic cell numbers in both the spleen and liver. Because CD40 is present on various hematopoietic-derived cells, endothelial cells, and some tumors themselves, this study was performed to determine whether the antitumor effects of CD40 stimulation and IL-2 were primarily mediated by CD40+ hematopoietic-derived cells. Bone marrow chimeras were created by reconstituting lethally irradiated CD40+/+ recipients with bone marrow from CD40-/- or CD40+/+ mice. Chimeric mice were then implanted orthotopically with renal cancer cells, followed by treatment with anti-CD40 agonist monoclonal antibodies and IL-2. Immune parameters of the spleen and liver were assessed after therapy and correlated with antitumor responses. The antitumor effects in the CD40-/- bone marrow transplantation chimeras were almost completely abrogated after treatment, and this shows that hematopoietically derived CD40+ cells are the principal targets for CD40 stimulation in this model. Although both spleen and liver showed reductions in CD8+ T-cell and dendritic cell expansion in the CD40-/- versus CD40+/+ chimeras after therapy, only the liver exhibited no significant increases in either CD8+ T cells or dendritic cells after treatment. CD40 cells on hematopoietic cells are the primary target for anti-CD40 and IL-2 therapy. The results also suggest that the immunologic events in the liver may be more revealing that those in lymphoid organs with regard to critical events related to responses after therapy.

Animals↗

PubMed2004

An absence of CCR5 on donor cells results in acceleration of acute graft-vs-host disease.

OBJECTIVE: Chemokines have been postulated to play a role in the pathogenesis of graft-vs-host disease (GVHD) after allogeneic hematopoietic transplantation. Recent reports have indicated that the absence of donor expression of CCR5 on T cells ameliorates GVHD in models using no conditioning of the recipient. We therefore assessed the role of CCR5 on donor cells in models where intensive conditioning of the recipient occurs, thus more appropriately mirroring the clinical experience. METHODS: Lethally irradiated mice received allogeneic bone marrow transplants. Recipients were given full MHC-mismatched donor bone marrow and splenocytes from CCR5 knockout (KO) mice vs wild-type (WT) control donors. RESULTS: Recipients of CCR5 KO donor cells succumbed to acute GVHD at an accelerated rate compared to mice receiving WT cells. Donor CD8+ T cells expanded to a significantly greater extent in recipients of CCR5 KO vs WT control cells. T cells recovered from recipients of CCR5 KO cells produced more IFN-gamma and TNF-alpha and proliferated to a T-cell mitogen at a significantly greater level then T cells from recipients of WT cells, indicating that CCR5 plays a role in downregulating donor alloreactive CD8+ T-cell expansion. Histological assessment of the mice indicated pathological lesions in the kidneys and a greater degree of liver pathological changes in mice that received CCR5 KO donor grafts. CONCLUSIONS: These results indicate that the role of CCR5 in allogeneic bone marrow transplants and GVHD is more complex than initially thought. In a murine transplant model with intensive conditioning, the overall effect of absent CCR5 expression on donor cells results in greater GVHD and donor T-cell expansion.

Acute Disease↗

PubMed2004

Mammalian phylogenomics comes of age.

The relatively new field of phylogenomics is beginning to reveal the potential of genomic data for evolutionary studies. As the cost of whole genome sequencing falls, anticipation of complete genome sequences from divergent species, reflecting the major lineages of modern mammals, is no longer a distant dream. In this article, we describe how comparative genomic data from mammals is progressing to resolve long-standing phylogenetic controversies, to refine dogma on how chromosomes evolve and to guide annotation of human and other vertebrate genomes.

Animals↗

PubMed2004

Development of a new standard laboratory protocol for estimation of the field attenuation of hearing protection devices: sample size necessary to provide acceptable reproducibility.

The mandate of ASA Working Group S12/WG11 has been to develop "laboratory and/or field procedure(s) that yield useful estimates of field performance" of hearing protection devices (HPDs). A real-ear attenuation at threshold procedure was selected, devised, tested for one earmuff and three earplugs via an interlaboratory study involving five laboratories and 147 subjects, and incorporated into a new standard that was approved in 1997 [Royster et al., "Development of a new standard laboratory protocol for estimating the field attenuation of hearing protection devices. Part I. Research of Working Group 11, Accredited Standards Committee S 12, Noise," J. Acoust. Soc. Am. 99, 1506-1526; ANSI, S12.6-1997, "American National Standard method for measuring real-ear attenuation of hearing protectors" (American National Standards Institute, New York, 1997)]. The subject-fit methodology of ANSI S12.6-1997 relies upon listeners who are audiometrically proficient, but inexperienced in the use of HPDs. Whenever a new method is adopted, it is important to know the effects of variability on the power of the measurements. In evaluation of protector noise reduction determined by experimenter-fit, informed-user-fit, and subject-fit methods, interlaboratory reproducibility was found to be best for the subject-fit method. Formulas were derived for determining the minimum detectable difference between attenuation measurements and for determining the number of subjects necessary to achieve a selected level of precision. For a precision of 6 dB, the study found that the minimum number of subjects was 4 for the Bilsom UF-1 earmuff, 10 for the E.A.R Classic earplug, 31 for the Willson EP100 earplug, and 22 for the PlasMed V-51R earplug.

Auditory Threshold↗