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William J Murphy

Publications and source records attributed to William J Murphy.

66 records · Page 4Linked to original sources

The Feline Genome Project.

The compilation of a dense gene map and eventually a whole genome sequence (WGS) of the domestic cat holds considerable value for human genome annotation, for veterinary medicine, and for insight into the evolution of genome organization among mammals. Human association and veterinary studies of the cat, its domestic breeds, and its charismatic wild relatives of the family Felidae have rendered the species a powerful model for human hereditary diseases, for infectious disease agents, for adaptive evolutionary divergence, for conservation genetics, and for forensic applications. Here we review the advantages, rationale, and present strategy of a feline genome project, and we describe the disease models, comparative genomics, and biological applications posed by the full resolution of the cat's genome.

Animals↗

Bacterial lipopolysaccharide selectively up-regulates the function of the chemotactic peptide receptor formyl peptide receptor 2 in murine microglial cells.

Receptors for the bacterial chemotactic peptide fMLP are implicated in inflammation and host defense against microbial infection. We investigated the expression and function of fMLPR in microglial cells, which share characteristics of mononuclear phagocytes and play an important role in proinflammatory responses in the CNS. The expression of the genes encoding formyl peptide receptor (FPR)1 and FPR2, the high- and low-affinity fMLPR, was detected in a murine microglial cell line N9, but these cells did not respond to chemotactic agonists known for these receptors. N9 cells incubated with bacterial LPS increased the expression of fMLPR genes and developed a species of specific, but low-affinity, binding sites for fMLP, in association with marked calcium mobilization and chemotaxis responses to fMLP in a concentration range that typically activated the low-affinity receptor FPR2. In addition, LPS-treated N9 cells were chemoattracted by two FPR2-specific agonists, the HIV-1 envelope-derived V3 peptide, and the 42 aa form of the amyloid beta peptide which is a pathogenic agent in Alzheimer's disease. Primary murine microglial cells also expressed FPR1 and FPR2 genes, but similar to N9 cells, exhibited FPR2-mediated activation only after LPS treatment. In contrast to its effect on the function of FPR2, LPS reduced N9 cell binding and biological responses to the chemokine stromal cell-derived factor-1alpha. Thus, LPS selectively modulates the function of chemoattractant receptors in microglia and may promote host response in inflammatory diseases in the CNS.

Animals↗

Low responsiveness to IFN-gamma, after pretreatment of mouse macrophages with lipopolysaccharides, develops via diverse regulatory pathways.

We have investigated the mechanisms by which prior exposure of mouse macrophages to lipopolysaccharides (LPS) induces a state of low responsiveness to subsequent exposure to IFN-gamma. We demonstrate that induction of this state requires both de novo gene expression and the suppression of phosphorylation events that lead to activation of transcription factor Stat1 alpha. These observations are mechanistically consistent with the known induction of suppressors of cytokine signaling (SOCS)-1 and SOCS-3 proteins by LPS. In this regard, we demonstrate that overexpression of either SOCS protein suppresses induction of the mouse inducible nitric oxide synthase (iNOS) gene promoter: apparently by suppressing interactions between Stat1 alpha and IFN-gamma activated sites present in both the iNOS, and interferon regulatory factor-1, gene promoters. The induction of SOCS-1 and SOCS-3 by LPS or IFN-beta (an autocrine/paracrine mediator of LPS-induced SOCS-1 mRNA synthesis)occurs by way of multiple protein kinase pathways that include protein tyrosine kinases, protein kinase C, and mitogen-activated protein kinases. These results provide insight that may allow discrimination between LPS-induced inhibition of macrophage functions that are detrimental to the host (e.g. continued exposure to LPS) versus those that might potentially be beneficial (e.g. exposure to subsequent agonists that induce more specific macrophage functions).

Animals↗

Oxidative DNA damage is associated with intense noise exposure in the rat.

Increasing evidence suggests that noise-induced hearing loss may be reduced or prevented with antioxidant therapy. Biochemical markers of reactive oxygen species (ROS)-induced damage can help elucidate possible treatment timing constraints. This study examined the time course of ROS damage following a 2-h, broad-band noise exposure resulting in permanent threshold shift in 35 Long-Evans rats. Cochlea, brain, liver, serum and urine were analyzed at 1, 3, 8, 72, and 672 h (28 days) after exposure. Oxidative DNA damage was assessed by measuring 8-hydroxy-2'-deoxyguanosine (8OHdG) by high performance liquid chromatography with electrochemical detection. Lipid peroxidation was measured via the thiobarbituric acid-reactive substances (TBARS) colorimetric assay for detection of aldehydes (e.g., malondialdehyde). Auditory brainstem response and distortion product otoacoustic emission thresholds showed progressive elevation for the 3- and 8-h groups, then notable recovery for the 72-h group, and some worsening for the 672-h group. 8OHdG was significantly elevated in cochlea in the 8-h group, and in brain and liver for the 72-h group. TBARS were significantly elevated in serum for the 72-h group. Based upon oxidative DNA damage present in cochlea following intense noise, we postulate that the first 8 h following exposure might be a critical period for antioxidant treatment.

8-Hydroxy-2'-Deoxyguanosine↗

Susceptibility to the ototoxic properties of toluene is species specific.

Toluene is the most widely used industrial solvent. It has been shown to be ototoxic in mice and rats, and to increase permanent threshold shift in conjunction with exposure to noise. Chinchillas are widely used for studying noise effects on the cochlea. The present study was initiated to study toluene and noise interaction in chinchillas. Thirty-three chinchillas were exposed to a 95 dBA 500 Hz octave band noise plus 2000 ppm toluene, 8 or 12 h per day for 10 days. Auditory function was estimated using the auditory brainstem response (ABR) to tones between 500 Hz and 16 kHz. There was no effect on the ABR of toluene alone. Noise alone produced a threshold shift. There was no interaction of noise and toluene on the ear. The present study suggests that chinchillas are markedly less susceptible to the ototoxic effect of toluene than mice and rats. A working hypothesis as to the species differences was that chinchilla liver was able to detoxify the toluene. Hepatic microsomes from chinchillas, rats and humans were tested for their ability to convert toluene to the more water-soluble compound - benzyl alcohol. Chinchilla livers were found to contain more of the P450 enzymes CYP2E1 and CYP2B than rats or humans. In addition, the data show that the P450 enzymes are more active in chinchillas than in rats and humans. In conclusion, the results suggest that rats and mice are a more appropriate model for human toluene ototoxicity. However, chinchillas may provide a valuable model for investigating how ototoxic agents can be detoxified to less damaging compounds.

Animals↗

NK inhibitory-receptor blockade for purging of leukemia: effects on hematopoietic reconstitution.

One of the obstacles of BMT that limits its efficacy is failure to eradicate the original tumor. The incidence of tumor relapse is particularly high after autologous BMT. Natural killer (NK) cells comprise various subsets that can express inhibitory receptors for MHC class I determinants. We have recently demonstrated that blockade of NK-cell inhibitory receptors can augment antitumor effects in vitro and in vivo. However, breakdown of tolerance and autoreactivity may occur as a result of the inhibition of NK-cell inactivation to self MHC determinants. We have utilized F(ab')2 fragments of monoclonal antibody, 5E6, against Ly49C/I inhibitory receptors, which are expressed on 35% to 60% of NK cells in H2b strains of mice and are specific for H2Kb, to investigate the effect of inhibitory-receptor blockade on syngeneic bone marrow cell (BMC) and tumor cell growth. We show that treatment of interleukin 2-activated C57BL/6 (B6, H2b) SCID-mouse NK cells with 5E6 F(ab')2 fragments during 48-hour coculture resulted in autoreactivity against syngeneic BMCs as demonstrated by suppression of myeloid reconstitution on day 14 post-BMT. However, this suppressive effect was transient and normalized by day 21 post-BMT. In contrast, blockade of inhibitory receptors during 24-hour coculture had no adverse effects on myeloid reconstitution after BMT. Furthermore, under the same coculture conditions, NK cell-mediated purging of C1498 leukemia cells contaminating syngeneic BMCs was more effective with inhibitory-receptor blockade, leading to a significantly higher proportion of animals with long-term survival compared to the control recipients. These results demonstrate that short-term in vitro blockade of inhibitory receptors can augment antitumor activity without long-term inhibitory effects on BMCs and thus may be of potential use in the purging of contaminating tumor cells prior to autologous BMT.

Animals↗

Hearing protector attenuation: models of attenuation distributions.

Current hearing protector rating standards estimate the protection performance for a given frequency as the mean attenuation minus a multiple of the standard deviation. Distributions of real-ear attenuation at threshold data are fit with maximum likelihood estimation procedures using both normal and mixed-normal models. Attenuations from six hearing protectors, Bilsom UF-1 earmuff, Bilsom Quietzone, E.A.R Classic, E.A.R EXPRESS Pod Plugs, Howard Leight MAX, and Wilson EP100 earplugs, measured with a subject-fit protocol are reported. The mixed-normal (bimodal) model provides a better fit to the empirical data than the unimodal model for most frequencies and protectors. Primarily, the bimodal model fits the shape of the distributions caused by data from poorly-fit protectors. This paper presents an alternative method for estimating the protection performance either with the more accurate bimodal model or directly from the empirical cumulative distributions of the attenuation data.

Auditory Threshold↗

Expansion of LTC-ICs and maintenance of p21 and BCL-2 expression in cord blood CD34(+)/CD38(-) early progenitors cultured over human MSCs as a feeder layer.

Allogeneic transplantation with umbilical cord blood (UCB) is limited in adult recipients by a low CD34(+) cell dose. Clinical trials incorporating cytokine-based UCB in vitro expansion have not demonstrated significant shortening of hematologic recovery despite substantial increases in CD34(+) cell dose, suggesting loss of stem cell function. To sustain stem cell function during cytokine-based in vitro expansion, a feeder layer of human mesenchymal stem cells (MSCs) was incorporated in an attempt to mimic the stem cell niche in the marrow microenvironment. UCB expansion on MSCs resulted in a 7.7-fold increase in total LTC-IC output and a 3.8-fold increase of total early CD34(+) progenitors (CD38(-)/HLA-DR(-)). Importantly, early CD34(+)/CD38(-)/HLA-DR(-) progenitors from cultures expanded on MSCs demonstrated higher cytoplasmic expression of the cell-cycle inhibitor, p21(cip1/waf1), and the antiapoptotic protein, BCL-2, compared with UCB expanded in cytokines alone, suggesting improved maintenance of stem cell function in the presence of MSCs. Moreover, the presence of MSCs did not elicit UCB lymphocyte activation. Taken together, these results strongly suggest that the addition of MSCs as a feeder layer provides improved conditions for expansion of early UCB CD34(+)/CD38(-)/HLA-DR(-) hematopoietic progenitors and may serve to inhibit their differentiation and rates of apoptosis during short-term in vitro expansion.

ADP-ribosyl Cyclase↗

The role of growth hormone in T-cell development and reconstitution.

Growth hormone (GH), directly or through GH-induction of insulin-like growth factor (IGF)-1, has been implicated in lymphocyte development and function. Recent studies have questioned the role of GH and IGF-1 in immune responses. This review examines experimental data describing the immunoregulatory function of GH and attempts to reconcile the literature.

Animals↗

Administration of either anti-CD40 or interleukin-12 following lethal total body irradiation induces acute lethal toxicity affecting the gut.

Interleukin (IL)-12 and antibodies against CD40 have demonstrated antitumor effects in a variety of in vivo model systems. However, both agents can also mediate significant toxicities either when used following lethal TBI or when administered in combination with other agents such as IL-2. In this study, we assessed the effects of anti-CD40 monoclonal antibody (MoAb) and IL-12 in lethally irradiated mice. Acute lethal toxicity was observed following the administration of either 10 microg anti-CD40 MoAb (FGK45) or 0.5 microg of recombinant murine (rm)IL-12 that resulted in 100% mortality of all mice within 4 to 6 days. Histological evaluation revealed destruction of the normal gut architecture in both anti-CD40 MoAb- and rmIL-12-treated mice. Analysis of serum cytokine levels in the lethally irradiated mice receiving anti-CD40 MoAb demonstrated a marked increase of interferon (IFN)-gamma and IL-12 p40, whereas mice receiving rmIL-12 demonstrated a marked increase of IFN-gamma. Lethally irradiated IL-12 p40 knock-out mice were resistant to anti-CD40-induced toxicity, suggesting that the lack of IL-12 p40 with no possibility of making functional IL- 12 p70 is key for this toxic reaction. Similarly, lethally irradiated IFN-gamma knock-out mice were completely resistant to rmIL-12-induced toxicity, suggesting that IFN-gamma is a major player in IL-12-mediated toxicity. These results suggest that both anti-CD40 MoAb and rmIL-12 induce an acute fatal toxicity characterized by similar intestinal pathology and mediated in part by IFN-gamma.

Acute Disease↗

Combined administration of antibodies to human interleukin 8 and epidermal growth factor receptor results in increased antimetastatic effects on human breast carcinoma xenografts.

PURPOSE: Current antibody-based immunotherapeutic approaches under evaluation for breast carcinoma are limited in target scope. For example, administration of the human epidermal growth factor receptor (EGFR) antibody, alone or in combination with a chemotherapeutic drug, is thought to primarily inhibit tumor cell proliferation. The aim of this study was to assess the effects of a combined blockade designed to inhibit tumor growth by inhibition of proliferation rate and the proinflammatory effects of interleukin (IL) 8. EXPERIMENTAL DESIGN: A human breast carcinoma cell line that produces high levels of IL-8 was injected s.c. into severe combined immunodeficient mice. IL-8 has been reported to augment the progression of some human tumors; thus, we used a human IL-8 antibody, ABXIL8, in combination with anti-EGFR, ABXEGFR, to inhibit the metastasis of MDA231 tumors. RESULTS: Whereas anti-IL-8 alone had no appreciable antimetastatic effect, the combination of ABXIL8 significantly enhanced the antitumor effects of ABXEGFR, resulting in greater survival of SCID tumor-bearing mice. This effect on survival was correlated with decreased metastatic spread and decreased tumor size in mice receiving both antibodies. Intriguingly, in vitro studies indicate that this antibody combination markedly inhibited matrix metalloproteinase activity associated with MDA-231 cells to a greater degree than either antibody alone. CONCLUSION: Combined administration of these two human antibodies using growth factor blockade in conjunction with chemokine blockade may thus provide a more effective approach for treatment of metastatic human breast carcinoma.

Animals↗

Alternative field methods for measuring hearing protector performance.

In comparison with the mandatory noise reduction rating (NRR) testing of every hearing protector sold in the United States, real-world tests of hearing protector attenuation are scarce. This study evaluated data from three potential field-test methods as compared with the subject-fit data from Method B of ANSI S12.6-1997 for the E.A.R(R) Express trade mark Pod Plug trade mark. The new field-test methods were the FitCheck headphone (FCH) method, FitCheck in sound field (FCSF) method, and bone-conduction loudness balance (BCLB) method, all of which can be administered in small single-person audiometric booths such as are commonly found in industry. Twenty normal-hearing and audiometrically competent subjects naive to hearing protector use were tested with the laboratory and the three field-test methods in a repeated-measures design. Repeated-measures models with structured covariance matrices were used to analyze the data. Significant effects were found for method, frequency, and first-order frequency-by-gender and frequency-by-method interactions. These effects and interactions were expected given the different psychophysical tasks. The FCSF and BCLB methods provided attenuations that were not significantly different from those found with Method B. Although the attenuations measured for the FCH method were statistically different (greater) than the attenuations from the other methods, the differences were within the magnitude of acceptable test-retest audiometric variability. The results suggest that the FCH and FCSF methods were both feasible and reliable methods for field testing. The FCH method is limited to testing earplugs, and the FCSF requires additional equipment to outfit the test booth, but could be used for testing all types of protectors.

Adolescent↗