Search PubMed⌕ Search

Biomedical subjects

C G Smith

Publications and source records attributed to C G Smith.

At least 37 records · Page 2Linked to original sources
PubMed1995

Outbreak of brucellosis at a United States pork packing plant.

In 1992, the North Carolina Department of Environment, Health, and Natural Resources received 18 case reports of brucellosis from a county health department. All patients had potential exposure to the kill floor of one pork processing plant. A subsequent National Institute for Occupational Safety and Health health hazard evaluation surveyed 154 (99%) of 156 kill floor workers of this plant and found that 30 (19%) had evidence of recent (or persistent) brucellosis. These data show that significant exposure to Brucella is occurring among packing plant workers in North Carolina and suggest that some of the approximately 38,000 production workers in pork processing plants in the United States are at risk of contracting swine brucellosis. Additional measures may need to be taken to prevent occupational exposure to Brucella.

Adult↗
PubMed1994

Basal forebrain injections of the benzodiazepine partial inverse agonist FG 7142 enhance memory of rats in the double Y-maze.

Cholinergic replacement strategies have achieved little success in the treatment of Alzheimer's disease. It has been suggested that the mnemonic function of cholinergic neurons may be enhanced by treatments that reduce GABA-ergic inhibition, while preserving the normal pattern of activity in the cholinergic neurons. Following on these suggestions, the present study investigated the mnemonic effects of intra-nucleus basalis magnocellularis (NBM) injections of the benzodiazepine receptor partial inverse agonist N-methyl-beta-carboline-3-carboxamide (FG 7142). Rats were surgically implanted with bilateral cannulae in the NBM prior to training in a double Y-maze. Daily training sessions continued until reference and working memory choice performance stabilized to a criterion of > or = 91% correct. Rats (n = 9) received FG 7142 bilaterally in doses of 0.2, 2.0 and 3.0 micrograms/0.5 microliter per side, muscimol (a GABAA agonist) in a dose of 0.1 microgram/0.5 microliter per side, vehicle (345 micrograms 2-hydroxypropyl-beta-cyclodextrin/0.5 microliter saline per side) or no injection in a counterbalanced order with retraining to criterion between treatments. Muscimol impaired choice accuracy on both the reference and working memory components, but the effect was bigger for working memory, replicating our previous findings. Two doses of FG 7142 (0.2 and 2.0 micrograms/0.5 microliter) enhanced choice accuracy on the working memory component. The present results suggest that benzodiazepine partial inverse agonists may enhance mnemonic function.

Animals↗
PubMed1994

Persistently elevated soluble tumor necrosis factor receptor and interleukin-1 receptor antagonist levels in critically ill patients.

The appearance of endogenously produced inhibitors against tumor necrosis factor (TNF) (soluble TNF-receptor type I, sTNFR-I) and interleukin-1 (IL-1 receptor antagonist, IL-1ra) was evaluated acutely in five normal patients after experimental endotoxemia lipopolysaccharide (LPS) and prospectively during a one to 11 week period in 12 septic, critically ill patients. Increased levels of both factors remained detectable in the circulation for up to 24 hours after LPS (2 nanograms per kilogram body weight) administration in normal patients. Despite free TNF-a activity being detected only sporadically (3 percent of the samples) and that IL-1 beta was never detectable in the patients in the intensive care unit, IL-6 bioactivity was present in 90 percent of initial samples. Circulating sTNFR-I levels up to 62,000 picograms per milliliter and IL-1ra levels of 14,800 picograms per milliliter were noted in the critically ill patients and remained consistently detectable throughout the extended period of evaluation. While there was no difference in IL-1ra levels between patients who survived or ultimately died, sTNFR-I levels were significantly (p < 0.001) lower in survivors compared with nonsurvivors. A correlation between circulating sTNFR-I and concurrent cortisol levels (r = 0.64; p < 0.002) was also noted. Furthermore, a correlation between sTNFR-I and the severity of initial insult, as assessed by APACHE II scores (r = 0.54; p < 0.01) was demonstrable. These naturally occurring cytokine antagonists likely represent additional indicators of the presence of an infectious or other inflammatory process and seem to persist in the circulation even during conditions in which their respective proinflammatory cytokines are not demonstrable.

Adolescent↗
PubMed1993

Interleukin-1 beta induces interleukin-1 receptor antagonist and tumor necrosis factor binding protein in humans.

Sustained release or high levels of interleukin-1 (IL-1) and/or tumor necrosis factor (TNF), as observed after endotoxin challenge, can produce a variety of toxicities. Naturally occurring inhibitors to IL-1 and TNF, IL-1 receptor antagonist (IL-1ra) and soluble TNF receptor forms, have been detected. These proteins may function to buffer or limit the effects of these cytokines as part of a regulatory network. As part of a clinical trial of recombinant human interleukin-1 beta (rhIL-1 beta), serial plasma samples were obtained from 6 patients with metastatic melanoma treated with 30-min infusions of rhIL-1 beta for 5 consecutive days. The presence of circulating IL-1 receptor antagonist and soluble TNF binding proteins (TNF-R55-BP and TNF-R75-BP) were assessed. A maximum 86-fold increase for IL-1ra, a 7-8-fold increase for TNF-R55-BP, and a 2-3-fold increase for TNF-R75-BP were seen 2-4 h, 1 h, and 4 h, respectively, after rhIL-1 beta infusion. On each day of the treatment, the secretion of IL-1ra and release of TNF-R55-BP was observed, but there was no accumulation above baseline value for IL-1ra before each of the 5 daily infusions. Although there was a steady decrease of the 6-h postinfusion plasma levels for IL-1ra and TNF-R55-BP over the 5 treatment days, no increase of clinical side effects was noted. Two patients had measurable levels of TNF-alpha, but no correlation to TNF-binding proteins was observed. Our data show that early after rhIL-1 beta infusion the induction of IL-1ra secretion, as well as TNF-binding protein release, is observed.

Adult↗
PubMed1992

Chitin-binding proteins in potato (Solanum tuberosum L.) tuber. Characterization, immunolocalization and effects of wounding.

Tubers of potato (Solanum tuberosum L.) contain a number of chitin-binding proteins which have possible functions in defence against pathogens. A major protein of the tuber is the chitin-binding lectin which has been further characterized with respect to its antigenicity and N-terminal amino acid sequence. By using an antiserum monospecific for tuber lectin in unwounded potato the protein was found in the cytoplasm and vacuole, unusually for a hydroxyproline-rich glycoprotein, but consistent with its soluble nature in subcellular extracts. Little increased synthesis of the lectin precursor or the post-translationally modified form could be demonstrated in excised potato tuber discs. However, after wounding there is increased synthesis of another hydroxyproline-containing glycoprotein of Mr 57,000, which binds to chitin and shares common epitopes with the lectin. In comparison with the tuber lectin, this novel glycoprotein contains less hydroxyproline, but from its overall composition it is clearly not an underhydroxylated form of the tuber lectin. It differed in its N-terminal amino acid sequence and was much less glycosylated, although arabinose was still present. Synthesis of the Mr-57,000 polypeptide began after the initial burst of protein synthesis and increased, reaching a peak at 24 h after wounding. The protein was produced with its enzymes of post-translational modification, prolyl hydroxylase and arabinosyltransferase, concomitantly with the marker enzymes for wounding, phenylalanine ammonia-lyase and membrane-bound phenol oxidase and peroxidase.

Amino Acid Sequence↗
PubMed1992

3-Oxoacyl-[ACP] reductase from oilseed rape (Brassica napus).

3-Oxoacyl-[ACP] reductase (E.C. 1.1.1.100, alternatively known as beta-ketoacyl-[ACP] reductase), a component of fatty acid synthetase has been purified from seeds of rape by ammonium sulphate fractionation, Procion Red H-E3B chromatography, FPLC gel filtration and high performance hydroxyapatite chromatography. The purified enzyme appears on SDS-PAGE as a number of 20-30 kDa components and has a strong tendency to exist in a dimeric form, particularly when dithiothreitol is not present to reduce disulphide bonds. Cleveland mapping and cross-reactivity with antiserum raised against avocado 3-oxoacyl-[ACP] reductase both indicate that the multiple components have similar primary structures. On gel filtration the enzyme appears to have a molecular mass of 120 kDa suggesting that the native structure is tetrameric. The enzyme has a strong preference for the acetoacetyl ester of acyl carrier protein (Km = 3 microM) over the corresponding esters of the model substrates N-acetyl cysteamine (Km = 35 mM) and CoA (Km = 261 microM). It is inactivated by dilution but this can be partly prevented by the inclusion of NADPH. Using an antiserum prepared against avocado 3-oxoacyl-[ACP] reductase, the enzyme has been visualised inside the plastids of rape embryo and leaf tissues by immunoelectron microscopy. Amino acid sequencing of two peptides prepared by digestion of the purified enzyme with trypsin showed strong similarities with 3-oxoacyl-[ACP] reductase from avocado pear and the Nod G gene product from Rhizobium meliloti.

3-Oxoacyl-(Acyl-Carrier-Protein) Reductase↗
PubMed1992

A novel lamina lucida component of epithelial and endothelial basement membranes detected by LH39 monoclonal antibody.

The murine monoclonal antibody, LH39 was characterized in this study and appeared to bind to a novel basement membrane epitope. This antigen was expressed in the epithelial basement membrane of human tissue derived from all three germ cell layers and in basement membranes surrounding small blood vessels within the stroma of all organs examined. LH39 antigen could be first detected in fetal skin at the dermo-epidermal junction at 7 weeks estimated gestational age but was not present in the dermal vasculature until 16 weeks. When tested against tissue from a range of lower mammalian species, LH39 antigen appeared to be primate-specific. The epithelial basement membrane zone in organotypical cultures, where there is de novo synthesis of basement membrane components, contained abundant LH39 antigen in contrast to other basement membrane components, type IV collagen, laminin, and type VII collagen. Ultrastructural localization of LH39 epitope, using immunogold electron microscopy on unfixed freshly frozen tissue, was to the lamina lucida. No cross-reactivity could be detected between LH39 and laminin, fibronectin, and collagens I, III, IV, and V using the ELISA assay. In vitro studies with a range of proteolytic enzymes suggested that the antigen was non-collagenous in nature. LH39 precipitated a polypeptide with a molecular weight of 185 kD from extracts of metabolically labelled cultured keratinocytes, and polypeptides of 185 and 200 kD from the culture medium. The tissue distribution of LH39 antigen suggested that it may be an epitope within anchoring filaments. Potential applications of this antibody include the study of benign and malignant human vascular disorders, diseases and tumours associated with angiogenesis, epithelial neoplasms, and conditions of tissue regeneration and repair, such as wound healing.

Adult↗
PubMed1991

Immobilization of Fv antibody fragments on porous silica and their utility in affinity chromatography.

Recent advances in molecular biology have allowed antibody binding domains to be cloned and expressed in Escherichia coli. The use of Fv antibody fragments as ligands in immunoaffinity chromatography is reported. Fv fragments specific for hen-egg lysozyme were immobilized on porous silica and used to recover antigen from spiked serum in a single step. Comparison with a conventional immunoadsorbent (whole antibodies immobilized on silica) showed the Fv-silica to have a fivefold superior capacity. Analysis of sectioned Fv-silica particles by immunoelectron microscopy indicated that captured antigen was evenly distributed throughout the internal porous structure of the particle.

Animals↗
PubMed1990

3-Oxoacyl-(acyl-carrier protein) reductase from avocado (Persea americana) fruit mesocarp.

The NADPH-linked 3-oxoacyl-(acyl-carrier protein) (ACP) reductase (EC 1.1.1.100), also known as 'beta-ketoacyl-ACP reductase', has been purified from the mesocarp of mature avocado pears (Persea americana). The enzyme is inactivated by low ionic strength and low temperature. On SDS/PAGE under reducing conditions, purified 3-oxoacyl-ACP reductase migrated as a single polypeptide giving a molecular mass of 28 kDa. Gel-filtration chromatography gave an apparent native molecular mass of 130 kDa, suggesting that the enzyme is tetrameric. The enzyme is inactivated by dilution, but some protection is afforded by the presence of NADPH. Kinetic constants have been determined using synthetic analogues as well as the natural ACP substrate. It exhibits a broad pH optimum around neutrality. Phenylglyoxal inactivates the enzyme, and partial protection is given by 1 mM-NADPH. Antibodies have been raised against the protein, which were used to localize it using immunogold electron microscopy. It is localized in plastids. N-Terminal amino-acid-sequence analysis was performed on the enzyme, and it shows close structural similarity with cytochrome f. Internal amino-acid-sequence data, derived from tryptic peptides, shows similarity with the putative gene products encoded by the nodG gene from the nitrogen-fixing bacterium Rhizobium meliloti and the gra III act III genes from Streptomyces spp.

3-Oxoacyl-(Acyl-Carrier-Protein) Reductase↗
PubMed1990

Immunological detection of NADH-specific enoyl-ACP reductase from rape seed (Brassica napus)--induction, relationship of alpha and beta polypeptides, mRNA translation and interaction with ACP.

An antibody has been raised against rape seed enoyl-ACP reductase. This recognizes both the alpha and beta polypeptides of the enzyme. Immunoblotting of fresh seed demonstrates that beta is not present in seed material, and that it is produced by proteolysis during isolation. It is thus deduced that rape seed enoyl reductase is an alpha 4 homotetramer. Leaf material from both rape and Arabidopsis have an enoyl reductase with a similar electrophoretic mobility to the rape seed enzyme when analyzed on SDS-PAGE. Quantitative immunoassay has demonstrated that the enzyme continually increases during lipid deposition, indicating that an increase in this enzyme is required to sustain high levels of lipid biosynthesis. In vitro translation experiments show that the enzyme is nuclear coded and synthesized as a precursor form. Immunogold electron microscopy has demonstrated that enoyl reductase is located in plastids. It is shown that ACP-Sepharose may be used as a matrix in the purification of enoyl-ACP reductase.

Acyl Carrier Protein↗
PubMed1990

The establishment of a population-based Cancer Registry for North Carolina.

In 1984 the North Carolina Medical Society's House of Delegates adopted Report S, which called for the North Carolina Legislature to fund a statewide cancer incident reporting system. The Cancer Committee continues to be advisory to the Division of Adult Health. A subcommittee of the Cancer Committee advises the Central Cancer Registry.

Forecasting↗
PubMed1989

Identification of cholera toxin-binding sites in the nucleus of intestinal epithelial cells.

Post-embedding immunogold electron microscopy shows several binding sites for cholera toxin in mouse intestinal epithelial cells, particularly in the heterochromatin of the nucleus as well as in the plasma membrane. Anti-ganglioside GM1 antibodies also bound to the nucleus, but did not interfere with the binding of toxin. 125I-labelled toxin bound specifically to a nuclear preparation from rabbit intestinal cells.

Animals↗
PubMed1988

Effect of selenium status on mRNA levels for glutathione peroxidase in rat liver.

To determine the effect of Se status on the level of mRNA for Se-dependent glutathione peroxidase (EC 1.11.1.9), rats were fed either a Se-deficient torula yeast diet (less than 0.02 mg Se/kg diet) or a Se-adequate diet (+0.2 mg Se/kg as Na2SeO3) for greater than 135 d. Liver glutathione peroxidase activity was 0.025 for Se-deficient versus 0.615 EU/mg protein for Se-adequate rats. Total liver RNA and polyadenylated RNA were isolated and subjected to Northern blot analysis using a 700 bp DNA probe from cloned murine glutathione peroxidase. Autoradiography showed that Se-deficient liver had 7-17% of the mRNA for glutathione peroxidase present in Se-adequate liver, suggesting that Se status may regulate the level of mRNA for this selenoenzyme.

Actins↗
PubMed1988

Plastid-localised seed acyl-carrier protein of Brassica napus is encoded by a distinct, nuclear multigene family.

Acyl-carrier protein (ACP) is a key component involved in the regulation of fatty acid biosynthesis in plants. cDNA clones encoding ACP from Brassica napus (oil seed rape) embryos have been isolated using oligonucleotide probes derived from heterologous ACPs. Analysis of the DNA sequence data, in conjunction with N-terminal amino acid sequence data, revealed ACP to be synthesized from nuclear DNA as a precursor containing a 51-amino-acid N-terminal extension. Immunocytochemical studies showed ACP to be localised solely within the plastids of B. napus seed tissue and it would therefore appear that the N-terminal extension functions as a transit peptide to direct ACP into these organelles. Analysis of several cDNA clones revealed sequence heterogeneity and thus evidence for an ACP multigene family. From ten cDNA clones, six unique genes, encoding five different mature ACP polypeptides, were identified. Northern blot hybridisation studies provide evidence that the seed and leaf forms of rape ACP are encoded by structurally distinct gene sets.

Acyl Carrier Protein↗
PubMed1988

Immortalization of rat keratinocytes by transfection with polyomavirus large T gene.

Transfection of primary rat keratinocytes with the polyomavirus large T gene promotes the establishment of cell lines. The keratinocytes express the large T protein and can be continuously cultured in medium containing a low concentration of calcium. The immortalized keratinocytes retain the ability to differentiate when the calcium concentration is increased to normal levels.

Animals↗