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Biomedical subjects

M O'Reilly

Publications and source records attributed to M O'Reilly.

At least 37 records · Page 2Linked to original sources
PubMed2000

Tuberculosis of the breast presenting as carcinoma.

Breast infections caused by Mycobacterium tuberculosis, although rare in western countries, should not be forgotten as a cause of a breast lump presenting clinically and radiologically as a carcinoma in the older patient who gives a history of previous tuberculosis. We report the case of an 84-year-old woman with a breast lump showing noncaseating granulomas on histology who developed a sinus track after excision biopsy of the lump. The patient responded to empiric treatment with anti-tuberculosis drugs and remains well 2 years after presentation.

Aged↗
PubMed1999

A sandwich enzyme-linked immunoabsorbent assay for measurement of picogram quantities of murine granulocyte colony-stimulating factor.

Granulocyte colony-stimulating factor (G-CSF) stimulates the proliferation and differentiation of hematopoietic progenitor cells of the neutrophil lineage. Measurement of murine G-CSF levels will allow examination of its role in host defense using murine models. Therefore, we developed a sensitive sandwich enzyme-linked immunoabsorbent assay (ELISA) for murine G-CSF. A polyclonal antibody to recombinant murine G-CSF was produced in rabbits and isolated using a protein A column. This purified native IgG served as the capture antibody and a portion of the IgG was biotinylated to serve as the developing antibody. Specificity was verified by lack of reactivity to GM-CSF, IL-6, IL-3, prolactin, and growth hormone. The lower limit of sensitivity routinely extended to 16 pg/ml in multiple ELISAs. Intra-assay coefficient of variation (CV) ranged from 3.4 to 21.5% across the detection limits of the assay, with the greatest variance occurring near the standard curve maximum. Interassay CV ranged from 11.5 to 23.3%. The ability of the ELISA to detect G-CSF in different sample preparations was examined in RPMI 1640 with 10% FCS, Hanks balanced salt solution, PBS/Tween-20/2% FCS, and the dilution media for ELISA (10% BLOTTO/PBS/0.05% Tween-20). Average recovery in these media ranged from 98 to 107%. Heparin anti-coagulated normal mouse plasma had a suppressive effect on the ELISA that varied between individual mice. Recovery was also determined from liver, spleen, and lung homogenate suspensions at dilutions of 1:5, 1:10, and 1:20 in dilution buffer. Recovery from liver was optimal at the 1:10 and 1:20 dilutions at 105%, with that of the 1:5 dilution at 135%. Recovery from spleen ranged from 94 to 96%. Lung homogenate displayed enhanced recovery (139% or greater) across all dilutions. The ability of the assay to detect G-CSF was explored by measurement of G-CSF levels in peritoneal lavage following polymicrobial intra-abdominal infection. Peak levels of G-CSF production occurred at 16 h after cecal ligation and puncture surgery with 18- and 21-guage needles (75.7 ng/ml and 111.4 ng/ml, respectively) as compared to the sham animals (0.61 ng/ml). The assay was found to be specific, sensitive, and accurate for measurement of murine G-CSF in a variety of sample types.

Animals↗
PubMed1999

The crystal structure of the Escherichia coli maltodextrin phosphorylase-acarbose complex.

Acarbose is a naturally occurring pseudo-tetrasaccharide. It has been used in conjunction with other drugs in the treatment of diabetes where it acts as an inhibitor of intestinal glucosidases. To probe the interactions of acarbose with other carbohydrate recognition enzymes, the crystal structure of E. coli maltodextrin phosphorylase (MalP) complexed with acarbose has been determined at 2.95 A resolution and refined to crystallographic R-values of R (Rfree) = 0.241 (0.293), respectively. Acarbose adopts a conformation that is close to its major minimum free energy conformation in the MalP-acarbose structure. The acarviosine moiety of acarbose occupies sub-sites +1 and +2 and the disaccharide sub-sites +3 and +4. (The site of phosphorolysis is between sub-sites -1 and +1.) This is the first identification of sub-sites +3 and +4 of MalP. Interactions of the glucosyl residues in sub-sites +2 and +4 are dominated by carbohydrate stacking interactions with tyrosine residues. These tyrosines (Tyr280 and Tyr613, respectively, in the rabbit muscle phosphorylase numbering scheme) are conserved in all species of phosphorylase. A glycerol molecule from the cryoprotectant occupies sub-site -1. The identification of four oligosaccharide sub-sites, that extend from the interior of the phosphorylase close to the catalytic site to the exterior surface of MalP, provides a structural rationalization of the substrate selectivity of MalP for a pentasaccharide substrate. Crystallographic binding studies of acarbose with amylases, glucoamylases, and glycosyltranferases and NMR studies of acarbose in solution have shown that acarbose can adopt two different conformations. This flexibility allows acarbose to target a number of different enzymes. The two alternative conformations of acarbose when bound to different carbohydrate enzymes are discussed.

Acarbose↗
PubMed1999

Telomerases.

Telomerases are RNA-dependent polymerases that catalyse the synthesis of the telomeric DNA at the tips of eukaryotic chromosomes. The recent identification of the catalytic subunit of telomerases from several different species suggests that the core of the telomerase is conserved. The proposed sequence and structural homology between the telomerase catalytic subunit and reverse transcriptases, together with a wealth of genetic and biochemical information, has led to significant advances in our understanding of the mechanism by which telomerases synthesise telomeric DNA.

Amino Acid Sequence↗
PubMed1999

Indirect versus direct measurement of brachial plexus depth.

UNLABELLED: Supraclavicular nerve blocks are effective but may be complicated by pneumothorax. We hypothesized that, to avoid this complication, the depths of the brachial plexus and the lung could be estimated to guide needle placement. In 17 patients undergoing surgical relief of thoracic outlet syndrome, we designated a point on the skin midway between the clavicle and the trapezius muscle, in line with the most lateral point of the arterial pulsation in the supraclavicular fossa, to make preoperative height measurements relative to the clavicle and then intraoperative depth measurements of the plexus, artery, and pleura. The height of the reference point above the top of clavicle did not differ significantly from the depth of the plexus. The height of the reference point above the top, middle, and bottom of the clavicle differed significantly from the pleural depth (P = 0.0001, P = 0.0001, P = 0.0005, respectively). Patient weight correlated significantly with the depth of the plexus (P = 0.004, r2 = 0.45), artery (P = 0.0003, r2 = 0.42), and pleura (P = 0.0003, r2 = 0.58). We conclude that it is possible to accurately estimate the depth of the brachial plexus in the supraclavicular fossa. IMPLICATIONS: In this study, we sought to minimize the risk of pneumothorax when approaching the brachial plexus through the supraclavicular fossa by developing a technique that could accurately estimate the depth of the nerves, within a range that is well clear of the lung.

Adult↗
PubMed1999

Immunopathologic responses to non-lethal sepsis.

Although sepsis causes significant morbidity and mortality, its basic pathology is still not well understood. We investigated the inflammatory and physiologic alterations of non-lethal sepsis using cecal ligation and puncture (CLP), a model that induces peritonitis due to mixed intestinal flora, reproducing the complex immunology of sepsis. Groups of mice were subjected to CLP (25G needle) or sham surgery, had minimitters implanted to continuously monitor temperature and activity, and were sacrificed daily for 6 days. There was significant hypothermia (6-13 hrs post-surgery), and decreases in activity (to day 4) and weight (to day 3) but no mortality in the CLP group. Blood analyses of the CLP-treated mice showed reduced hemoglobin, platelets, lymphocytes, monocytes, and neutrophils, compared to sham animals. Both groups had nearly equivalent neutrophil influx into the peritoneum. Plasma and peritoneal G-CSF, IL-6, as well as the murine chemokines KC and MIP2-alpha were significantly higher in the CLP-treated mice at day 1. Plasma and peritoneal TNF were low (<70 pg/mL). While there was elevated IL-1beta in the peritoneum of the CLP-treated mice, this cytokine was not detected in the plasma in either treatment group. Cytokines were not detected in the pulmonary airspace of the CLP-treated mice and PMNs were not recruited to this site. Our data shows altered immunopathology in non-lethal sepsis with significant blood and cytokine alterations. Since there was 100% survival, the inflammatory response was appropriate and probably even protective.

Animals↗
PubMed1998

Angiostatin induces endothelial cell apoptosis and activation of focal adhesion kinase independently of the integrin-binding motif RGD.

Angiostatin, a fragment of plasminogen, has been identified and characterized as an endogenous inhibitor of neovascularization. We show that angiostatin treatment of endothelial cells in the absence of growth factors results in an increased apoptotic index whereas the proliferation index is unchanged. Angiostatin also inhibits migration and tube formation of endothelial cells. Angiostatin treatment has no effect on growth factor-induced signal transduction but leads to an RGD-independent induction of the kinase activity of focal adhesion kinase, suggesting that the biological effects of angiostatin relate to subversion of adhesion plaque formation in endothelial cells.

Angiostatins↗
PubMed1998

Liver biopsy pathology in human immunodeficiency virus infection.

OBJECTIVES: To determine the hepatic changes in patients with human immunodeficiency virus (HIV) infection in Dublin and to assess the usefulness of liver biopsy in this condition. DESIGN: A consecutive series of liver biopsies was examined retrospectively and correlated with clinical findings. METHODS: A histological review was conducted of specimens from all patients who had undergone liver biopsy in a tertiary referral centre for HIV-infected patients in Dublin. RESULTS: Thirty-nine liver biopsies were studied from 36 patients. Thirty-one (86%) showed pathological changes. Non-specific changes were most frequent, followed by viral-induced chronic hepatitis (15 cases). Acute hepatitis was documented in five and cirrhosis in four cases. Five biopsies performed for pyrexia of unknown origin (PUO) or suspected tuberculosis showed granulomas. Organisms were rarely identified (2) and bile duct changes were uncommon. CONCLUSIONS: Liver biopsy was useful in detecting primary hepatic pathology and, in some cases, the cause of PUO, but not useful in detecting opportunistic infections despite their known presence in other organs.

Acute Disease↗
PubMed1998

TGF-beta1 up-regulates the mRNA for the Na+/Ca2+ exchanger in neonatal rat cardiac myocytes.

Northern analyses of neonatal cardiac myocytes demonstrated that TGF-beta1 (5 ng/ml) stimulates and IL-1beta (5 ng/ml) decreases the steady-state levels of the mRNA coding for the Na+/Ca2+ exchanger. This is in agreement with the effects of TGF-beta1 and IL-1beta on beating rate and calcium uptake, suggesting that such effects might be mediated, at least partially, through up-regulation of the Na+/Ca2+ exchanger. Basal and TGF-beta1 stimulated mRNA levels were inhibited by the PKC inhibitors H7 (10 microM) and GF109203X (250 nM). In addition, apigenin (12.5 microM), a MAP kinase inhibitor, was able to inhibit basal mRNA levels for the exchanger. Cycloheximide (35.5 microM) had no effect on basal mRNA levels for the exchanger but steady-state levels were diminished in cells treated with TGF-beta1. Finally, actinomycin D (10 microM) inhibited both basal and TGF-beta1 stimulated mRNA levels, though with a more pronounced effect in the presence of TGF-beta1. These results suggest that a complex mechanism of regulation exists for the exchanger and that PKC and possibly MAP kinases might be involved. The up-regulation of this important protein for calcium extrusion, induced by TGF-beta1, might prepare cells to better overcome the calcium overload which occurs under cellular stress and might explain some of the cytoprotective effects of TGF-beta1.

Animals↗
PubMed1997

The complete genome sequence of the gram-positive bacterium Bacillus subtilis.

Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large proportion of the genetic capacity is devoted to the utilization of a variety of carbon sources, including many plant-derived molecules. The identification of five signal peptidase genes, as well as several genes for components of the secretion apparatus, is important given the capacity of Bacillus strains to secrete large amounts of industrially important enzymes. Many of the genes are involved in the synthesis of secondary metabolites, including antibiotics, that are more typically associated with Streptomyces species. The genome contains at least ten prophages or remnants of prophages, indicating that bacteriophage infection has played an important evolutionary role in horizontal gene transfer, in particular in the propagation of bacterial pathogenesis.

Bacillus subtilis↗
PubMed1997

Nursing management of second stage labor.

Despite considerable research into nursing management of second stage labor, traditional approaches continue to predominate. Women are still encouraged to deliver in a recumbent position using sustained, closed-glottis pushing. Current research suggests that utilizing an upright position with pushing that is open glottis and complementary with the involuntary bearing-down reflex produces good maternal/fetal outcomes. Issues such as position, second stage phases, and bearing-down techniques are discussed in view of recent research findings. Gaps in knowledge are identified and practice implications are clearly defined. Now is the time to apply research-based knowledge to nursing management of second stage labor.

Journal Article↗
PubMed1997

Oligosaccharide substrate binding in Escherichia coli maltodextrin phosphorylase.

The crystal structure of E. coli maltodextrin phosphorylase co-crystallized with an oligosaccharide has been solved at 3.0 A resolution, providing the first structure of an oligosaccharide bound at the catalytic site of an alpha-glucan phosphorylase. An induced fit mechanism brings together two domains across the catalytic site tunnel. A stacking interaction between the glucosyl residue and the aromatic group of a tyrosine residue at a sub-site remote (8 A) from the catalytic site provides a key element in substrate recognition; mutation of this residue to Ala decreases the Kcat/Km by 10(4). Extrapolation of the results to substrate binding across the site of attack by phosphorolysis indicates a likely alteration in the glycosidic torsion angles from their preferred values, an alteration that appears to be important for the catalytic mechanism.

Crystallization↗
PubMed1997

Effects of exogenous cytokines on intravascular clearance of bacteria in normal and splenectomized mice.

BACKGROUND: Pretreatment with interleukin-1 (IL-1), granulocyte colony-stimulating factor (G-CSF), and granulocyte macrophage colony-stimulating factor (GM-CSF) can improve alveolar macrophage bactericidal activity against pneumococci. These effects vary in eusplenic and asplenic mice. Likewise, these cytokines have been shown to improve survival after an aerosol pneumococcal challenge. Mice dying in these studies had positive blood cultures and disseminated infection. The purpose of this study was to determine the effect of cytokine pretreatment on intravascular clearance of bacteria from eusplenic and asplenic mice. METHODS: Two weeks after splenectomy or sham operation, mice were pretreated for various times with IL-1, G-CSF, or GM-CSF or their corresponding vehicles. Mice then received tail-vein injections of bacteria (0.1 mL), and quantitative blood cultures were performed 15 and 30 minutes thereafter. RESULTS: Splenectomized mice had impaired clearance of both pneumococci and Pseudomonas compared with sham-operated mice (p < 0.05). IL-1 enhanced clearance in splenectomized mice (p < 0.001) but not in sham-operated mice (p not significant). G-CSF enhanced bacterial clearance in sham-operated mice (p < 0.01) but not in splenectomized mice (p not significant). GM-CSF enhanced clearance in both groups (p < 0.001). CONCLUSION: The net effects of exogenous cytokine therapy for infections depends on the state of the host defenses at the time of therapy. These agents may be useful as adjuvants for the treatment of infections, but further study is warranted.

Animals↗
PubMed1997

Expression of AbrB, a transition state regulator from Bacillus subtilis, is growth phase dependent in a manner resembling that of Fis, the nucleoid binding protein from Escherichia coli.

The transition state regulator AbrB functions as an activator, a repressor, and a preventer of gene expression in Bacillus subtilis. In this paper, we show that expression of abrB is growth phase dependent. Accumulation of abrB transcript is restricted to a short period spanning the transition between the lag and exponential phases of the growth cycle. The level of abrB transcript then falls sharply, and transcript cannot be detected at the mid-exponential period of the growth cycle. The level of AbrB protein is also maximal during early exponential growth but decreases gradually throughout the remainder of the growth cycle. The abrupt reduction of abrB transcript level during the early period of the growth cycle is effected by the phosphorylated form of the response regulator Spo0p3and to a lesser extent by negative autoregulation. The growth cycle-dependent expression of abrB is very similar to that observed for fis in Escherichia coli and in Salmonella typhimurium. Although AbrB and Fis are not homologous proteins, they display extensive similarity in terms of size, DNA binding characteristics, growth cycle-dependent patterns of expression, and their control over the expression of a varied group of operons. We hypothesize therefore that AbrB, like Fis, is a nucleoid binding protein.

Bacillus subtilis↗