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Biomedical subjects

C K Smith

Publications and source records attributed to C K Smith.

At least 19 recordsLinked to original sources
PubMed2003

A randomised clinical trial of nicotine patches for treatment of spit tobacco addiction among adolescents.

BACKGROUND: This study tested the efficacy of nicotine patches in combination with behavioural therapy for the treatment of adolescent spit tobacco addiction. Prior interventions had resulted in mean cessation rates below 15% at one year. METHODS: This study, the PATCH Project, used a three group, placebo controlled, randomised clinical trial design. The control group received a standard 3-5 minute counselling followed by a two week follow up phone call. The two intervention groups received a six week behavioural intervention; in addition, one group received active nicotine patches while the other group received placebo patches. Both groups received quarterly stage based telephone counselling. RESULTS: At one year, the usual care group's spit tobacco cessation rate was 11.4% (exact 95% confidence interval (CI) 6.1% to 19.1%), placebo patch 25.0% (95% CI 16.9% to 34.7%), and the active patch 17.3% (95% CI 10.4% to 26.3%). When both patch groups were combined, the cessation rate was 21.2% (95% CI 15.7% to 27.6%). The cessation rates for active and placebo patch were not significantly different (exact two sided p = 0.22), while the combined patch groups had a significantly greater cessation rate than usual care (exact two sided p = 0.04). CONCLUSIONS: The behavioural intervention proved to be about twice as successful as previous interventions, but the nicotine patch offered no improvement in cessation rates. The behavioural intervention is based on publicly available materials and can be easily adapted for widespread use, particularly in high schools.

Administration, Topical↗
PubMed2002

Quantification of rosuvastatin in human plasma by automated solid-phase extraction using tandem mass spectrometric detection.

An assay employing automated solid-phase extraction (SPE) followed by high-performance liquid chromatography with positive ion TurboIonspray tandem mass spectrometry (LC-MS-MS) was developed and validated for the quantification of rosuvastatin (Crestor) in human plasma. Rosuvastatin is a hydroxy-methyl glutaryl coenzyme A reductase inhibitor currently under development by AstraZeneca. The standard curve range in human plasma was 0.1-30 ng/ml with a lower limit of quantification (LLOQ) verified at 0.1 ng/ml. Inaccuracy was less than 8% and imprecision less than +/-15% at all concentration levels. There was no interference from endogenous substances. The analyte was stable in human plasma following three freeze/thaw cycles and for up to 6 months following storage at both -20 and -70 degrees C. The assay was successfully applied to the analysis of rosuvastatin in human plasma samples derived from clinical trials, allowing the pharmacokinetics of the compound to be determined.

Chromatography, Liquid↗
PubMed2001

High-performance liquid chromatography method for the quantification of non-radiolabelled cinnamic compounds in analytes derived from human skin absorption and metabolism experiments.

An isocratic high-performance liquid chromatography method has been developed for the quantification of the skin sensitisers trans-cinnamaldehyde and trans-cinnamic alcohol, and their cinnamic metabolites. The relative standard deviations (RSDs) between the gradients of eight sets of standard curves were 2.8, 3.1 and 1.9% for cinnamic alcohol, cinnamaldehyde and cinnamic acid, respectively. Sample analytes were derived from two series of experiments: in vitro full-thickness human skin absorption and metabolism studies and metabolism studies using human skin homogenates, with non-radiolabelled cinnamic compounds. Skin absorption and metabolism experiments were performed in the absence and presence of the alcohol dehydrogenase inhibitor, pyrazole. Samples from full-thickness skin absorption studies were analysed without extraction; cinnamic compounds from within skin were extracted into methanolic solutions using newly developed methods. The intra-assay RSDs ranged from 0.17 to 2.52% for cinnamic alcohol, 0.24 to 9.14% for cinnamaldehyde and 0.26 to 6.43% for cinnamic acid. The inter-assay RSDs for cinnamic alcohol, cinnamaldehyde and cinnamic acid, respectively, as determined from n=20 HPLC runs, were 2.10, 4.16 and 2.26%.

Acrolein↗
PubMed2001

Skin-sensitization structure-activity relationships for aldehydes.

A selection of 17 aldehydes (13 sensitizing and 4 non-sensitizing), all of which possessed a benzene ring, were evaluated using structure-activity relationships (SARs). The sensitizing compounds were classified as strong, moderate or weak skin sensitizers on the basis of in vivo data. The aldehydes were grouped into 4 distinct subcategories of functionally related aldehydes that were termed aryl-substituted aliphatic, aryl, aryl with special features (that can undergo metabolism) and alpha,beta-unsaturated aldehydes. It was observed that a structure-activity relationship could be derived for a subset of aldehydes that could react via the same chemical mechanism. This further supports the view that applying knowledge on reaction mechanisms to develop SAR models can provide a more accurate means of investigating and predicting the sensitization potential of structurally and functionally related chemicals.

Aldehydes↗
PubMed2000

Human skin absorption and metabolism of the contact allergens, cinnamic aldehyde, and cinnamic alcohol.

trans-Cinnamaldehyde and trans-cinnamic alcohol have been commonly reported to cause allergic contact dermatitis (ACD) in humans. Cinnamaldehyde is a more potent skin sensitizer than cinnamic alcohol. It has been hypothesized that cinnamic alcohol is a "prohapten" that requires metabolic activation, presumably by oxidoreductase enzymes such as alcohol dehydrogenase (ADH) or cytochrome P450 2E1 (CYP2E1), to the protein-reactive cinnamaldehyde (a hapten). In this study, the in vitro percutaneous absorption and metabolism of cinnamaldehyde and cinnamic alcohol (78 micromol dose) has been examined using freshly excised, metabolically viable, full-thickness breast and abdomen skin from six female donors. Penetration rates and total cumulative recoveries of cinnamic compounds that were present in receptor fluid, extracted from within the skin, evaporated from the skin surface, or remained unabsorbed on the skin surface after 24 h were quantified by reversed-phase high-performance liquid chromatography. Biotransformation of cinnamaldehyde to both cinnamic alcohol and cinnamic acid was observed. Topically applied cinnamic alcohol was converted to cinnamaldehyde (found on the skin surface only) and cinnamic acid. To establish whether these biotransformations were enzymatic, experiments were performed in the absence and presence of varying concentrations (80-320 micromol) of the ADH/CYP2E1 inhibitors pyrazole or 4-methylpyrazole. The observation that pyrazole significantly reduced (p < 0.05) the total penetration of cinnamic metabolites into receptor fluid, following either cinnamaldehyde or cinnamic alcohol treatment, but did not significantly affect parent chemical penetration, suggests that we are measuring cutaneous metabolic products of ADH activity. The skin absorption and metabolism of cinnamaldehyde and cinnamic alcohol will play an important role in the manifestation of ACD following topical exposure to these compounds.

Acrolein↗
PubMed2000

Cloning and characterization of a novel histone acetyltransferase homologue from the protozoan parasite Toxoplasma gondii reveals a distinct GCN5 family member.

In an effort to identify gene products involved in transcriptional regulation in apicomplexan parasites, the Toxoplasma gondii expressed sequence tag (EST) database was examined for sequences containing similarity to known transcriptional components. One EST (dbEST ID #466792) exhibited strong similarity to yeast GCN5 and other histone acetyltransferases (HATs). Primers were designed based on the EST sequence and used to amplify an 850 bp fragment (containing an intron) from T. gondii genomic DNA which was used to identify four cDNA clones from a tachyzoite cDNA library. The complete open reading frame (ORF) of 3.5 kb was elucidated using 5' RACE and genomic sequence. The deduced amino acid sequence of the coding region shows that the C-terminal domain possesses unequivocal similarity to GCN5 family members. However, unlike other lower eukaryotes, T. gondii GCN5 has an extended N-terminal domain similar in length, but not in composition, to metazoan HAT proteins. These features distinguish T. gondii GCN5 as a novel member of the GCN5 family. A portion of the cDNA sequence was used as a probe to isolate three overlapping clones from a T. gondii genomic library, generating a approximately 7.5 kb map of the GCN5 locus which contains seven exons separated by six introns. Southern analysis verifies the predicted map and suggests that a similar locus may be present elsewhere in the genome.

Acetyltransferases↗
PubMed2000

Anti-inflammatory effects of ergotamine in steers.

The objective of this experiment was to investigate whether the ergot alkaloid, ergotamine (ET), an alkaloid used to model fescue toxicosis in cattle, modifies the response of cattle to endotoxin (LPS) challenge. Steers (n = 16) were divided into the following treatment groups: control (C), ergotamine (ET), endotoxin (LPS), and ET + LPS. ET and ET + LPS groups received a single bolus intravenous injection of ET (40 microg. kg. body wt(-1)), whereas C and LPS steers received a single bolus injection of sterile vehicle. Thirty minutes after ET/vehicle administration, a single bolus intravenous injection of LPS (0.2 microg. kg. body wt(-1)) was given. Blood was collected at various time points for 48 hr post. Endotoxin increased rectal temperature (RT) and the circulating levels of tumor necrosis factor-alpha (TNF-alpha), cortisol, haptoglobin (Hp), thromboxane B(2) (TXB(2)). The circulating Hp, TNF-alpha, and TXB(2) increases were blunted by pretreatment with ET compared with ET + LPS. Ergotamine by itself increased circulating cortisol and RT, whereas it decreased serum prolactin (PRL). Therefore, whereas administration of LPS at 0.2 microg/kg to steers resulted in an expected response, the combination of ET + LPS attenuated major effects of LPS alone. Thus, acute administration of ET appeared to be anti-inflammatory as it decreased the inflammatory response to LPS, an effect likely driven at least in part by the ET-caused cortisol increase.

Animal Feed↗
PubMed1999

Expression and localization of human alcohol and aldehyde dehydrogenase enzymes in skin.

Alcohol dehydrogenase (ADH; EC 1.1.1.1) and aldehyde dehydrogenase (ALDH; EC 1.2.1.3.) are important enzymes involved in the biotransformation of both alcohols and aldehydes. Today, six classes of ADH and twelve classes of ALDH have been defined in mammals. Here we report the detection and localisation of three classes of ADH and two classes of ALDH in human skin, using Western blot analysis and immunohistochemistry with class-specific antisera. Western blot analysis of human skin cytosol revealed that class I-III ADH and class 1 and class 3 ALDH enzymes are expressed, constitutively, in three different anatomical regions of human skin (foreskin, breast, abdomen). Densitometric analysis of the immunoreactive bands revealed differential constitutive expression of these enzymes in foreskin, breast, and abdomen skin. Immunohistochemistry showed the presence of class I ADH and class III ADH enzymes, predominantly in the epidermis with some localised expression in the dermal appendages of human skin. In comparison, staining for class II ADH was more faint in the epidermis with very little dermal expression. Class 1 ALDH and class 3 ALDH were predominantly localised to the epidermis with minimal, highly localised dermal appendageal expression. These cutaneous ADH and ALDH enzymes may play significant roles in the metabolism of endogenous or xenobiotic alcohols and aldehydes.

Adolescent↗
PubMed1999

Lon and Clp family proteases and chaperones share homologous substrate-recognition domains.

Lon protease and members of the Clp family of molecular chaperones and protease regulatory subunits contain homologous regions with properties expected for substrate-binding domains. Fragments corresponding to these sequences are stably and independently folded for Lon, ClpA, and ClpY. The corresponding regions from ClpB and ClpX are unstable. All five fragments exhibit distinct patterns of binding to three proteins that are protease substrates in vivo: the heat shock transcription factor sigma32, the SOS mutagenesis protein UmuD, and Arc repressor bearing the SsrA degradation tag. Recognition of UmuD is mediated through peptide sequences within a 24-residue N-terminal region whereas recognition of both sigma32 and SsrA-tagged Arc requires sequences at the C terminus. These results indicate that the Lon and Clp proteases use the same mechanism of substrate discrimination and suggest that these related ATP-dependent bacterial proteases scrutinize accessible or disordered regions of potential substrates for the presence of specific targeting sequences.

ATP-Dependent Proteases↗
PubMed1999

Accelerated growth of dermatofibrosarcoma protuberans during pregnancy.

Dermatofibrosarcoma protuberans (DFSPs) are uncommon skin tumors that have a high incidence of local recurrence even with wide surgical margin, but DFSPs rarely metastasize. Previous reports have suggested that DFSPs may enlarge more rapidly during pregnancy. We report 3 additional cases of DFSPs that showed accelerated growth during pregnancy. Immunohistochemical stains for CD34, S-100 protein, factor XIIIa, and estrogen and progesterone receptors were performed on biopsy specimens. The tumors in all 3 patients, and 4 additional DFSPs from 2 male and 2 female subjects, showed expression of progesterone receptor. As with many other stromal neoplasms, DFSPs appear to express low levels of hormone receptors, which may be one factor that accounts for their accelerated growth during pregnancy.

Adult↗
PubMed1999

Increased responsiveness to intravenous lipopolysaccharide challenge in steers grazing endophyte-infected tall fescue compared with steers grazing endophyte-free tall fescue.

Fescue toxicosis in cattle occurs as a result of consumption of ergot alkaloids in endophyte-infected (E+, Neotyphodium coenophialum) tall fescue (Festuca arundinacea). The condition is characterized by pyrexia, decreased weight gains, rough hair coats, and decreased calving rates. The objective of this experiment was to investigate whether steers grazing E+ fescue have altered host response to lipopolysaccharide (endotoxin, LPS) challenge compared with steers grazing endophyte-free (E-) fescue. Angus steers (n=8) had continuously grazed either E+ (n=4) or E- (n=4) tall fescue grass for 8 months prior to the experiment. The E+ steers had lower body weight, depressed average daily gain, and decreased basal serum prolactin compared with the E- steers prior to LPS administration. Each steer received a single bolus i.v. injection of LPS (0.2 microgram/kg body weight; Escherichia coli; 026:B6) dissolved in sterile saline, and blood was serially collected every 30 min for 4 h and at 24 h post LPS administration. LPS increased serum tumor necrosis factor-alpha (TNF-alpha), cortisol, and haptoglobin but decreased plasma glucose and IGF-I. Importantly, however, TNF-alpha, cortisol, and IGF-I responses to LPS were greater in E+ compared with E- steers. These results indicated that animals grazing E+ fescue had altered integrated metabolic host response compared with animals grazing E- fescue. Potentially, combined exposure to E+ fescue and a bacterial LPS could have greater deleterious effects on the animal compared with exposure to only one of the two and would likely lead to increased catabolism.

Animals↗
PubMed1998

Synthesis and endectocidal activity of novel 1-(arylsulfonyl)-1-[(trifluoromethyl)sulfonyl]methane derivatives.

We have recently synthesized a series of novel disulfonylmethane compounds that have shown anthelmintic and insecticidal (endectocidal) activity. Several analogues have shown activity against the internal nematode Haemonchus contortus. In sheep studies, these analogues have shown 100% control of this internal parasite at a 10 mg/kg rate. In vitro activity against the biting flies, Stomoxys calcitrans and Haematobia irritans, has been observed at rates as low as 25 and 2.3 ppm, respectively. Only marginal activity against the liver fluke Fasciola hepatica and Trichostrongylus colubriformis was seen. Respiratory control index values on rat liver mitochondria for this series suggested uncoupling of oxidative phosphorylation as a mechanism of action. Compound 1 is considered to be a promising agent for treatment of parasitized sheep.

Animals↗
PubMed1998

Immunostimulatory effects of pig seminal proteins on pig lymphocytes.

Pig seminal proteins PSP-I and PSP-II are major protein components of boars' ejaculate and are present as heterodimers (PSP-dimer) in seminal plasma. These proteins were examined for their ability to modulate pig lymphocyte activity in vitro in mitogen-induced lymphocyte proliferation assays and in one-way mixed lymphocyte reactions. Pig lymphocytes were cultured with phytohaemagglutinin, concanavalin A, or pokeweed mitogen (PWM) in the presence or absence of pig seminal proteins and the amount of cellular [3H]thymidine was used as an indication of proliferation. In the absence of mitogens, none of the three pig seminal proteins affected lymphocyte proliferation suggesting that these proteins are not antigenic or mitogenic. PSP-dimer enhanced lymphocyte proliferation induced by PWM (156-227%, P < 0.05) in a concentration-dependent manner, but had no effect on phytohaemagglutinin- or concanavalin A-induced proliferation. PSP-I enhanced (127-185%, P < 0.05) phytohaemagglutinin-induced proliferation. PSP-II augmented (130-240%, P < 0.05) lymphocyte proliferation induced by concanavalin A and PWM. Lymphocytes from gilts were significantly more responsive to concanavalin A- and PWM-induced lymphocyte proliferation in the presence of PSP-I compared with boars (concanavalin A: gilts 131%, boars 91%; PWM: gilts 188%, boars 134%; P < 0.05). In the mixed lymphocyte reaction, pretreating stimulating cells with increasing concentrations of PSP-I or PSP-II elicited a 400% concentration-dependent increase (P < 0.01) in lymphocyte proliferation. The abundance of pig seminal proteins in boar seminal plasma, their ability to enhance lymphocyte proliferation, and their previously reported ability to bind to lymphocytes suggest that these proteins are immunostimulatory and supports the hypothesis that they modulate uterine immune activity to ensure reproductive success.

Animals↗
PubMed1998

Beta-adrenergic receptor gene expression in bovine skeletal muscle cells in culture.

Beta-adrenergic receptors (betaAR) are abundant in fetal, neonatal, and adult skeletal muscles of cattle; however, only minimal levels of functional betaAR were detected in multinucleated muscle cell cultures prepared from 90- to 150-d fetal bovine skeletal muscle. Two other lines of evidence were consistent with low levels of betaAR expression in bovine muscle cultures. First, treating the cells with 10(-6)M isoproterenol for up to 20 min did not increase intracellular cAMP concentration. Second, neither the quantity of myosin heavy chain (MHC) nor its apparent synthesis rate were changed by treating the cells for 4 d with 10(-7) or 10(-6) M isoproterenol. Despite these results, the mRNA for the beta2AR could be detected in muscle cultures by PCR and on slot blots. Thus, the beta2AR mRNA was expressed, but significant levels of functional receptors could not be detected. Glucocorticoids are known to activate expression of OAR genes in several tissues, and the effect of dexamethasone on OAR gene expression in bovine multinucleated muscle cell cultures was evaluated. The intracellular concentration of cAMP following treatment with isoproterenol was elevated 10-fold by dexamethasone, and the population of functional receptors was elevated by approximately 50%. The effect of dexamethasone on muscle protein synthesis and accumulation was analyzed after pretreating the cells with dexamethasone for 24 h, followed by treatment with dexamethasone and 10(-6)M isoproterenol for an additional 48 h. The quantity of MHC synthesized and the apparent synthesis rate of MHC were stimulated by 10 to 35%. These effects seem to be due to posttranscriptional events, because the quantity of beta2AR receptor mRNA on slot blots was not increased by treatment with dexamethasone. Results of this study emphasize the importance of verifying that muscle cells contain functional betaAR when they are used to study the effects of betaAR agonists on muscle protein metabolism.

Adrenergic beta-Agonists↗
PubMed1998

Vaccination against ergot alkaloids and the effect of endophyte-infected fescue seed-based diets on rabbits.

Three sequential experiments were conducted with rabbits to 1) determine the effect of endophyte-infected (E+) tall fescue seed on rabbit performance and examine the effect of anti-ergot alkaloid immunization on rabbit performance and protectiveness against fescue toxicosis, 2) compare immunogens designed to elicit systemic anti-ergot alkaloid antibodies, and 3) select a superior adjuvant. In Exp. 1, rabbits (n = 6/treatment) fed E+ fescue seed diets (20%, 340 ppb total ergot alkaloids) had reduced (P < .05) intake and weight gain compared with endophyte-free (E-) controls, whereas apparent diet digestibility was not different between E+ and E-. Rabbits immunized against ergot alkaloids (E+ vac) with lysergol conjugated to human serum albumin (Ly-HSA) had greater (P < .05) intake than E+ rabbits during the wk 1 of a 3-wk dietary challenge. In Exp. 2, rabbits (n = 4/treatment) were immunized with Ly-HSA, with H100-B (ergot alkaloid hapten, H100-different protein carrier, B conjugate), or combinations of both with alum as adjuvant. Greatest (P < .001) anti-ergot alkaloid antibody (Ab) titer developed in the group immunized with H100-B. In Exp. 3, rabbits (n = 4/treatment) were immunized with the immunogen H100-B in conjunction with six adjuvants. Freund's incomplete adjuvant (FIA) in combination with DEAE-dextran and FIA alone gave highest anti-ergot titers. In summary, rabbit weight gain and intake were reduced by feeding E+ fescue seed diets, immunization against ergot alkaloids provided temporary improvement in intake, and H100-B conjugate with FIA or FIA + DEAE-dextran as adjuvants elicited a superior anti-ergot immune response. We believe that rabbits may serve as a model animal for fescue toxicosis research.

Acremonium↗
PubMed1998

Ipsilateral ureteroureterostomy for single ureteral reflux or obstruction in a duplicate system.

PURPOSE: The traditional treatment for obstruction or reflux involving a single ureter in a duplicated system has been common sheath reimplantation. More recently, ipsilateral ureteroureterostomy has been suggested as an alternative treatment. We reviewed cases with duplicate systems that were treated with ipsilateral ureteroureterostomy at our institution to determine the acceptability of this operation as an alternative to common sheath reimplantation. MATERIALS AND METHODS: A total of 22 patients with 24 duplicate systems underwent ipsilateral ureteroureterostomy between March 1986 and December 1996. Patient charts were reviewed and analyzed for patient age, sex, ureteral and renal anatomy, initial presentation, the clinical situation necessitating operation, and the occurrence of early and late complications. Patients were followed for a mean period of 41.4 months. RESULTS: Two adults and 20 children 10 years old or younger presented with urinary tract infection (13), hydronephrosis on maternal ultrasound (5), dribbling (2), ureteral calculus (1) and hydronephrosis on neonatal abdominal ultrasound (1). Mean hospital stay was 3 days. There was 1 early and 1 late complication. CONCLUSIONS: Ipsilateral ureteroureterostomy is an acceptable alternative to common sheath reimplantation in select patients with single ureteral disease in a duplicate system.

Adolescent↗
PubMed1997

PDZ-like domains mediate binding specificity in the Clp/Hsp100 family of chaperones and protease regulatory subunits.

ClpX, a molecular chaperone and the regulatory subunit of the ClpXP protease, is shown to contain tandem modular domains that bind to the C-terminal sequences of target proteins in a manner that parallels functional specificity. Nuclear magnetic resonance studies show that these C-terminal sequences are displayed as disordered peptides on the surface of otherwise folded proteins. The ClpX substrate-binding domains are homologous to sequences in other Clp/Hsp100 proteins and are related more distantly to PDZ domains, which also mediate C-terminal specific protein-protein interactions. Conservation of these binding domains indicates that the mode of substrate recognition characterized here for ClpX will be a conserved feature among Clp/Hsp100 family members and a distinguishing characteristic between this chaperone family and the Hsp70 chaperones.

ATPases Associated with Diverse Cellular Activitie↗