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K R Hansen

Publications and source records attributed to K R Hansen.

12 recordsLinked to original sources
PubMed2006

Use of IgG avidity ELISA to differentiate acute from persistent infection with Salmonella Dublin in cattle.

AIMS: To investigate whether an immunoglobulin (Ig)G avidity ELISA can be used to differentiate between acute and persistent infection with Salmonella (S.) Dublin in cattle. To determine whether the IgG isotype, IgG(1) and IgG(2) responses in acute and persistent infections differ. METHODS AND RESULTS: Animals were selected from two herds with long-term infection (years) and two herds recently infected (<3 months). Forty-seven animals were categorized into groups based on the persistence of their antibody level in milk. Based on titre from two serial dilutions the avidity index (AI) was calculated for IgG (IgG-AI), IgG(1) (IgG(1)-AI) and IgG(2) (IgG(2)-AI). The mean IgG-AI for suspected carrier animals with either persistently high (group 1) or persistently high to medium high (group 2) antibody levels was significantly (P = 0.003) higher (32.1% and 38.4%) than for acutely infected animals (21.7% and 22.3%). The probability of being a suspect carrier was associated with IgG-AI, antibody level in the sample and age. However, the effect of age could be the result of a biased sample selection. Specificities and sensitivities were calculated at a range of cut-off values for IgG-AI and IgG(1)-AI. Overall, IgG(2)-AI was high compared with IgG(1)-AI, and there was no difference in IgG(2)-AI between infection groups. There was no difference in the ratio IgG(2):IgG(1) for acute and persistent infection groups. CONCLUSIONS: Assuming that a persistently high antibody response is indicative of persistent infection with S. Dublin in cattle, it can be concluded that the IgG-AI can aid in differentiating between acute and long-term infection on herd level. However, for the test to be useful as an alternative tool to repeated sampling over time for detection of persistently infected carriers during control strategies in cattle herds, the test needs to be optimized and studied further in a larger sample of well-characterized infections in cattle. The affinity of IgG(2) is higher than IgG(1) early in the S. Dublin infection. There appears to be no difference in the IgG(2)-AI between the acute and chronic infection stages. SIGNIFICANCE AND IMPACT OF THE STUDY: For decades the strategies for detection of persistently infected cattle in S. Dublin infected herds have involved repeated bacteriological culture of faecal samples or repeated antibody measurements over several months. Both methods are time consuming and costly, leaving a new method for detection of carrier animals based on a single sampling highly desirable. This study illustrates a tool, IgG-AI, which may prove useful, although more validation of the method is required before it is used in practice.

Acute Disease↗
PubMed1998

Longitudinal estimates of pulmonary function in refractory ceramic fiber manufacturing workers.

Refractory ceramic fibers (RCF) are man-made vitreous fibers (MMVF) used in high-temperature industrial applications. Between 1987 and 1994, a prospective study evaluated pulmonary function of 361 male workers currently employed in RCF manufacturing and related operations for plausibility of a causal relationship between RCF exposure and pulmonary function changes. Workers included in the analysis provided at least five pulmonary function tests. The exposure-response relationship was modeled with two exposure variables: years in a production job, and cumulative fiber exposure (fiber-mo/cc). Comparison groups were nonproduction workers and workers with up to 15 fiber-mo/cc cumulative exposure. A statistically significant decrease in FVC was demonstrated among workers employed in production jobs more than 7 yr prior to initial test. A similar but nonstatistically significant result was demonstrated for FVC in workers with greater than 60 fiber-mo/cc cumulative exposure prior to initial pulmonary function test. Similar but nonstatistically significant results were obtained for FEV1. These findings, which primarily reflect workers employed before 1980, did not persist with analysis of follow-up production years and accumulated RCF exposure from initial pulmonary function test. Since longitudinal analyses are sensitive to influences that continue to affect annual decline during the study period, lower RCF exposure levels since the 1980s may be responsible for eliminating any further effect on pulmonary function.

Adult↗
PubMed1995

Isolation and characterization of the promoter of the human 5'-nucleotidase (CD73)-encoding gene.

Ecto-5'-nucleotidase (NT, CD73) is a purine salvage-pathway enzyme located on the surface of various cell types, including subsets of human lymphocytes and certain leukemias and lymphomas. In addition to purine salvage, NT has proposed roles in lymphocyte maturation and activation, and its expression has been associated with the resistance of some tumor cell lines to chemotherapeutic agents. To better understand the regulation of NT gene expression in normal lymphocyte development and the elevated expression seen in some drug-resistant tumor cell lines, we isolated NT genomic clones containing the promoter region. The genomic DNA upstream from the NT start codon is high in G+C content, with one cAMP-responsive element and five consensus Sp-1 binding sites, but no TATAA box. RNase protection assays identified a cluster of potential transcription start points (tsp). One tsp, at -63 bp relative to the start codon, was confirmed as authentic by 5'-RACE (rapid amplification of cDNA ends) cloning. Transient transfection experiments utilizing luc as a reporter gene have demonstrated that a 155-bp NT genomic DNA segment inclusive of the tsp functions as a promoter in both NT+ (WI-L2 and MG) and NT- (Jurkat, Hela and Raji) cell lines. The addition of 5'-flanking sequences extending as far as -1.9 kb did not confer cell-type-specific expression to the core promoter. However, nuclear run-on analysis of nascent NT transcripts suggested that differential transcription initiation is at least partially responsible for the regulation of NT expression. Thus, additional information is necessary, either at the chromatin level, or within elements outside of the promoter region, to direct tissue-specific expression of NT.

5'-Nucleotidase↗
PubMed1995

Production and characterization of multiple antigenic peptide antibodies to the adenosine A2b receptor.

A polyclonal antibody to the human adenosine A2b receptor (A2bR) was produced by immunizing a chicken with a multiple antigenic peptide consisting of eight copies of a 16-amino acid peptide, corresponding to the presumed second extracellular loop of the A2bR, linked to a branched lysine core. Western blotting with affinity-purified antibody revealed the human A2bR to be a protein of approximately 50-55 kDa, found in a variety of tissues including thymus, colon, and small intestine. The antibody also recognized mouse and rat A2bRs and revealed heterogeneity in size, with a 35-kDa protein being detected in small intestine in addition to the larger 50-52-kDa species in thymus, colon, and placenta. The chicken anti-human A2bR peptide antibody recognized the receptor in both frozen and formalin-fixed tissue sections. In human colon, the A2bR was highly expressed in epithelial cells of the crypts. A2bR immunoreactivity was also apparent in syncytiotrophoblast cells of human placental villi and in the basal zone of murine chorioallantoic placenta. These cell type-specific patterns of expression are consistent with the hypothesized roles of the A2bR in mediating electrogenic Cl- secretion and the resulting secretory diarrhea caused by colonic crypt abscesses and in regulating morphogenesis of the placenta. Insight into the multiple physiological consequences of A2bR engagement will be forthcoming from an analysis of the cell type-specific expression of this receptor in additional tissues.

Amino Acid Sequence↗
PubMed1993

Murine ecto-5'-nucleotidase (CD73): cDNA cloning and tissue distribution.

The murine cDNA, encoding the purine catabolic enzyme, ecto-5'-nucleotidase (NT), was cloned and the tissue-specific distribution of both the mRNA and enzyme activity was examined. Starting with kidney RNA and primers based on the known rat sequence, reverse transcriptase-polymerase chain reaction (RT-PCR) was utilized to obtain the complete sequence for the translated portion of the murine cDNA. Murine NT is 94% identical to human NT at the amino acid (aa) level and 86% identical at the nucleotide (nt) level. NT enzyme assays revealed greater than tenfold more NT activity in mature vs. immature murine T- and B-lymphocytes. A similar increase in NT activity was also found when the pre-B-cell line, 70Z/3, was induced to produce surface kappa light chains with lipopolysaccharide (LPS) and gamma-interferon (gamma-IFN). Thus, culture systems in which murine lymphocytes mature may be useful for examining the mechanisms of NT gene regulation, as well as the function of NT in the immune system. In tissues, enzyme activity varied over 30-fold, from the lowest levels in skeletal muscle, thymus and spleen to highest in placenta, kidney and forestomach. Levels of mRNA, as determined by RNase protection assay, showed increased NT expression in the early gestation site, as compared to non-pregnant uterus, and in day-19.5 placenta, as compared to day-13 chorioallantoic placenta. Messenger RNA levels were in general proportional to enzyme activity, except in the lung and glandular stomach where mRNA levels were higher than expected, based on enzyme activity.(ABSTRACT TRUNCATED AT 250 WORDS)

5'-Nucleotidase↗
PubMed1992

[Treatment of injuries in the county of Ringkøbing. 1. Incidence of injuries during a period of 4 weeks].

During a period of four weeks (17 September-14 October 1990) all treatments of injured persons in the five hospitals in the County of Ringkøbing were registered. In addition, the refund accounts for all additional services connected with injuries submitted by the 166 general practitioners to the Danish National Health Insurance were also registered. A total incidence rate (calculated on an annual basis) of injuries requiring treatment was found to be 229/1000 og the population per annum. As compared with a similar investigation carried out in 1969, increases in incidence rates of 2.1 for admissions, 3.8 for outpatient hospital treatments and 4.4 for treatment of injuries in general practice were found. An increase in the number of minor injuries is thus concerned, probably partly conditioned by an altered threshold for seeking treatment and partly a slighter increase in the number of more serious injuries. In addition, a significant difference in the frequency of injuries requiring treatment with more numerous treatments was found in the regions of Lemvig and Ringkøbing as compared with the remainder of the county. It is recommended that registration from casualty departments with collection of data for analysis of accidents be undertaken with the object of elucidating the background for the increase in the injuries and the differences between the individual regions in the county.

Accidents↗
PubMed1992

[Treatment of injuries in the county of Ringkøbing. 2. Function of the closed casualty department].

The closed casualty department function in the County of Ringkøbing was investigated during a period of four weeks. It was demonstrated that this functioned according to plan as the distribution general practice/casualty department was 3.4:1 and 70% of the patients in the casualty department were referred via general practice. The result of this was that the majority of minor injuries (removal of foreign bodies and treatment of wounds) were treated in general practice. In the casualty departments, there were fewer minor injuries and injuries which did not require specific treatment than are the case in open casualty departments. However, a definite diurnal variation was observed in the function of the closed casualty department as patients showed a greater tendency to seek treatment in the casualty department after working hours than during working hours and the general practitioners referred twice as many patients after working hours for continued treatment in the casualty departments. It is concluded that the closed casualty department system in the County of Ringkøbing functions well but that problems may be anticipated with the function if the duty-rosters for the general practitioners are altered so that the distances between general practitioners on duty increase and these have an increased work-load.

Denmark↗
PubMed1986

[Desmoid tumor].

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Adult↗