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Biomedical subjects

K Pedersen

Publications and source records attributed to K Pedersen.

At least 91 records · Page 5Linked to original sources
PubMed1996

A 3-year follow-up of patients with localized prostate cancer operated on with or without pre-treatment with the GnRH-agonist triptorelin.

OBJECTIVE: To examine the effect of pre-operative androgen deprivation on the progression rate of malignancy in patients operated on for localized prostate cancer. PATIENTS AND METHODS: A total of 53 patients received no hormone therapy (group 1) and a further 38 patients (group 2) received the generic releasing-hormone agonist triptorelin during the 3 months before surgery. The patients in group 1 had T1b-T2 tumours, whereas 12 of those in group 2 had clinical stage T3 tumours. Despite this, the surgical specimens from the patients in group 2 showed a rate of cancer invasion of the surgical margins 20% lower than those from the patients in group 1. After prostatectomy, the patients were followed for 3 years by repeated analyses of prostate-specific antigen (PSA) in serum. RESULTS: During the follow-up, the PSA level exceeded the upper threshold (0.6 ng/mL) in 16% of the patients in group 1 and in 43% of those in group 2 (P < 0.05). This difference was mainly related to the pre-treatment stage of the tumor. Some of the patients in group 1 received post-operative radiotherapy but this was not reflected in their PSA levels. Of the patients in group 1 and 2, 4% and 14% respectively (P > 0.05), developed symptoms from skeletal metastases. CONCLUSION: There was no evidence that pre-operative hormone therapy slowed the progression of prostate cancer.

Aged↗
PubMed1996

Transcriptional regulation of the human cholecystokinin gene: composite action of upstream stimulatory factor, Sp1, and members of the CREB/ATF-AP-1 family of transcription factors.

We have examined cis-elements and trans-acting factors that regulate transcription of the human cholecystokinin (CCK) gene. Transient expression of CCK promoter deletion constructs in human SK-N-MC neuroblastoma cells depicted positive cis-elements between the positions -100 to -92, -84 to -74, and -58 to -37, 5' to the transcription initiation site. Correspondingly, DNase I protection analysis showed that transacting factors bound to elements within these regions. The sequences encompass a putative basic helix-loop-helix leucine zipper (bHLH-ZIP) element, an Sp1 element, and a combined cAMP- and TPA-responsive element (CRE/TRE) at positions -97 to -92, -39 to -34, and -80 to -73, respectively. Mobility and supershift assays demonstrated that upstream stimulatory factor (USF) and Sp1 bind to the former elements and competition experiments confirmed that CREB/ATF and AP-1 bind to the CRE/TRE element. Mutation of the bHLH-ZIP and CRE/TRE elements decreased the activity of the promoter by 65% and 42%, respectively. The activity of the promoter was increased six- and two-fold after stimulation with forskolin and TPA, respectively. Stimulation was eliminated after mutation of the CRE/TRE element. Co-transfection experiments with pRSV-c-jun, pSV-fos, and pRC-RSV-CREB constructs showed that jun, CREB, and AP-1 stimulate transcription. We conclude that USF, Sp1, and members of the CREB/ATF and AP-1 family of transcription factors are the major determinants of CCK gene transcription.

Base Sequence↗
PubMed1996

Characterization of atypical Aeromonas salmonicida isolates by ribotyping and plasmid profiling.

A total of 38 strains of atypical Aeromonas salmonicida, three oxidase-negative but otherwise typical Aer. salmonicida, three typical Aer. salmonicida, and two reference strains, isolated from several countries and fish species were examined with respect to rRNA gene restriction patterns (ribotypes) and plasmid profiles. Most epidemiologically unrelated strains had different ribotypes, whereas isolates from the same outbreak were identical. All strains, except one, carried one or more large plasmids (> 55 kbp) and all strains, except two, additionally carried one or more smaller plasmids. Many strains isolated from the same outbreak showed different plasmid profiles although some plasmids were identical. The results suggest the existence of several atypical Aer. salmonicida. It also seems that ribotypes are stable properties for these bacteria while the plasmids are more labile.

Aeromonas↗
PubMed1996

Diversity and distribution of subterranean bacteria in groundwater at Oklo in Gabon, Africa, as determined by 16S rRNA gene sequencing.

This paper describes how ground water was sampled, DNA extracted, amplified and cloned and how information available in the ribosomal 16S rRNA gene was used for mapping diversity and distribution of subterranean bacteria in groundwater at the Bangombé site in the Oklo region. The results showed that this site was inhabited by a diversified population of bacteria. Each borehole was dominated by species that did not dominate in any of the other boreholes; a result that probably reflects documented differences in the geochemical environment. Two of the sequences obtained were identified at genus level to represent Acinetobacter and Zoogloea, but most of the 44 sequences found were only distantly related to species in the DNA database. The deepest borehole, BAX01 (105 m), had the highest number of bacteria and also total organic carbon (TOC). This borehole harboured only Proteobacteria beta group sequences while sequences related to Proteobacteria beta, gamma and delta groups and Gram-positive bacteria were found in the other four boreholes. Two of the boreholes, BAX02 (34 m) and BAX04 (10 m) had many 16S rRNA gene sequences in common and also had similar counts of bacteria, content of TOC, pH and equal conductivity, suggesting a hydraulic connection between them.

Acinetobacter↗
PubMed1996

The risk of malignancy in the surgical margin at radical prostatectomy reduced almost three-fold in patients given neo-adjuvant hormone treatment.

OBJECTIVES: To investigate the outcome of neo-adjuvant hormone treatment before radical prostatectomy regarding local tumour extension, peri-operative blood loss and operation time. PATIENTS: Of 111 surgically treated patients with prostate cancer (T1b-T3a, N0, M0, G1-3), 55 were randomised to immediate radical prostatectomy and 56 to 3 months of neo-adjuvant treatment with triptorelin (3.75 mg i.m. every 28 days) and cyproterone acetate (50 mg b.i.d. for 3 weeks to prevent flare). RESULTS: No differences were found in blood loss or operation time but patients who had neo-adjuvant treatment had a significantly lower frequency of positive margins (41 vs. 23%, p = 0.013). CONCLUSION: Neo-adjuvant treatment does not facilitate radical prostatectomy but may improve the chance of local cure. This must, however, be documented with long-term follow-up in randomised patients.

Aged↗
PubMed1996

Atypical Aeromonas salmonicida isolated from diseased turbot (Scophtalmus maximus L.).

Atypical Aeromonas salmonicida were isolated from 3 outbreaks of disease among farmed turbot (Scophthalmus maximus L.) in 3 different farms, 1 from Norway (N1) and 2 from Denmark (DK1 and DK2). In all 3 cases, the incidence of disease and mortality was high and the main characteristic pathological finding was skin ulcers and septicaemia. The isolated bacteria were subjected to a thorough phenotypic and genotypic examination and comparison in the laboratory. All 3 isolates belonged to A. salmonicida but displayed some very different biochemical properties. However, the 2 Danish strains, DK1 and DK2 had identical ribotypes but different from that of N1, whereas the plasmid profiles of DK1 and N1 were identical but different from that of DK2. These observations emphasize the need for an improvement of our understanding of the taxonomy and epidemiology of atypical A. salmonicida.

Aeromonas↗
PubMed1995

Analysis of zeins' ER retention in Xenopus oocytes.

Zeins, maize storage proteins, are retained in the endoplasmic reticulum (ER) during the intracellular protein targeting process. Hydrophobic interaction has been postulated as the driving force of zeins' aggregation and retention in the ER. Recently, a class of zein (the 27K zein) has been proposed to facilitate zeins' ER retention by anchoring to the ER membrane. This study investigated the significance of the two proposed mechanisms toward zeins' ER retention using Xenopus oocyte. Following injection of the total or 27K zein mRNA, zein's movement within the ER was analyzed based upon the extent of diffusion to the non-injected oocyte half. This study indicates that the total zeins freely move within the lumen of the ER, thus, suggesting that the intermolecular aggregation, leading to insolubility and exclusion from the ER lumenal fluid, may not be essential for zeins' ER retention. This study also suggests that the 27K zein may not facilitate zeins' ER retention by virtue of an anchor to the ER membrane based on its free movement in the ER. Free movement of the total and 27K zeins, under conditions where zein aggregates should form, necessitates a reevaluation of the mechanisms responsible for zein polypeptides' ER retention and protein body formation.

Animals↗
PubMed1995

Sensitivity and stability of LiF thermoluminescence dosimeters.

Three different batches of LiF TLD-100 rods were subjected to investigation of their radiation sensitivity and the stability of the sensitivity after subsequent cycles of irradiation readouts. An old batch (circular rods from 1985), R85, showed an initial sensitivity of approximately 720 (nC/Gy). A new batch of circular rods (R0059) had an initial sensitivity more than a factor of 2.5 higher than the old batch. A batch of square rods (S3720) had an even higher sensitivity; a factor of almost 4 higher than batch R85. Both batches of circular rods showed a statistically significant change in sensitivity with increasing cycles of irradiations and readouts. No significant change was observed for the batch S3720. Batch R85 showed an increasing sensitivity with increasing number of cycles, and a small reduction in the width of the sensitivity distribution within the batch. However, the newer batch (R0059), showed a marked decrease in sensitivity and a doubling of the broadening of the sensitivity distribution after 10 cycles. No significant change in the sensitivity distribution within the S3720 batch was observed after 10 cycles.

Equipment Design↗
PubMed1995

Prevalence of eardrum pathology in a cohort born in 1955.

The aim of this study was to compare the prevalence of the different types of eardrum pathology in a cohort of adults not previously treated by grommet insertion with corresponding findings obtained in a cohort previously treated with grommet insertion. A cohort born in 1955 were invited to a screening examination including otomicroscopy. In the untreated cohort, retraction of Shrapnell's membrane was found in four per cent of the ears compared to 20 per cent in the cohort treated with grommets. Tensa pathology, including atrophy and myringosclerosis, was found in six per cent of the ears in the untreated cohort and in 17 per cent in the treated cohort. Normal eardrums were found in 91 per cent of the ears. Despite the increased awareness of secretory otitis, as well as the increased rate of surgical treatment, the prevalence of eardrum pathology seems to be increasing. The reasons for this are discussed.

Adenoidectomy↗
PubMed1995

Evidence against a potential endoplasmic reticulum transmembrane domain of 27K zein expressed in Xenopus oocytes.

During the cellular protein targeting process, zeins (maize storage proteins) are retained in the endoplasmic reticulum (ER) where they accumulate into protein bodies. There are circumstantial and preliminary data indicating that the 27K zein, a class of zein proteins, may span the ER membrane. This potential transmembrane domain is considered very significant with regard to the mechanism of ER retention for zeins. The potential transmembrane domain may permit the 27K zein to remain in the ER and to serve as an anchor for other classes of zein, thus acting as a nucleating factor for protein body formation. This study investigated the potential transmembrane feature in a heterologous system (Xenopus laevis oocyte). Following injection of synthetic 27K zein mRNA, isolated protein vesicles were subjected to proteinase K digestion, surface biotinylation and alkaline extraction. Throughout three categories of assay the possible role of the 27K zein as a transmembrane protein was consistently refuted in this study. The 27K zein polypeptide was affected by neither proteinase K digestion nor biotinylation and was released from alkali-stripped membranes. This study, therefore, concludes that the 27K zein is not a protein body nucleating factor by virtue of an ER transmembrane feature.

Animals↗
PubMed1995

Ribotyping and plasmid profiling of Vibrio anguillarum serovar O2 and Vibrio ordalii.

One hundred and twenty-nine strains of Vibrio anguillarum serovar O2 and 14 strains of Vibrio ordalii were ribotyped and examined for plasmid contents. A total of 35 different ribotypes were detected. The V. anguillarum serovar O2 strains were divided into 32 different ribotypes. The V. ordalii strains showed three different ribotypes, clearly distinct from those of the V. anguillarum strains. Ribotypes were separated into seven clusters, of which one comprised the V. ordalii strains. Clustering of the strains indicated a genetic difference between North European and South European V. anguillarum O2 strains. Sero-subgroups O2a and O2b shared ribotypes; however, three of the clusters did not include O2a strains. All V. ordalii strains had a plasmid of 32 kb. This plasmid was not detected in any of the V. anguillarum strains. Seventeen different plasmid profiles with 17 different sized plasmids were detected among the V. anguillarum strains. Most of the plasmids were small (< 6 kb) and found in several strains. Except for one South European strain, plasmids were detected only in the North European strains of V. anguillarum O2.

Cluster Analysis↗
PubMed1995

Comparison of Pulsed-Field Gel Electrophoresis, Ribotyping, and Plasmid Profiling for Typing of Vibrio anguillarum Serovar O1.

A total of 75 Vibrio anguillarum serogroup O1 strains were studied with respect to their plasmid contents, ribotypes, and pulsed-field gel electrophoresis (PFGE) patterns. Eight plasmid profiles and six ribotypes were demonstrated, and one profile was dominant by both typing methods. In contrast, PFGE had very high discriminatory power, demonstrating 35 profiles. On the basis of PFGE patterns, a similarity matrix and a dendrogram were constructed. The results indicated that Scandinavian strains and southern European isolates (with some exceptions) belong to two different clonal lineages. A few strains from the United States and United Kingdom deviated considerably from each other and from Scandinavian and southern European strains.

Journal Article↗
PubMed1995

Evidence for the existence of distinct populations of Vibrio anguillarum serogroup O1 based on plasmid contents and ribotypes.

A total of 103 Vibrio anguillarum serogroup O1 strains displaying 15 different plasmid profiles were characterized with respect to biochemical properties and ribotypes. The results confirmed that V. anguillarum O1 is a biochemically homogeneous group. The 103 strains could be allocated to three main clusters with high similarity coefficients. None of the biochemical properties were connected with the presence of plasmids. In total, 12 different ribotypes were demonstrated, with HindIII being used as the restriction enzyme. Forty of the strains were isolated from the same Danish fish farm, some from the kidneys of diseased fish and some from the environment, and some strains were isolated from the mucus, gills, and feces of healthy fish. Nineteen of these isolates possessed the 67-kb virulence plasmid alone or in combination with other plasmids, while 21 had no plasmids. All strains isolated from the kidneys of diseased fish on this farm had plasmids. Irrespective of their origin (kidneys, gills, or mucus), all 19 strains carrying the 67-kb virulence plasmid had the same ribotype, profile 1, while isolates without plasmids belonged to five different profiles, all different from profile 1. These results suggest that pathogenic V. anguillarum O1 strains possessing a virulence plasmid and nonpathogenic strains without plasmids from a small geographical area and even from the same fish may constitute two essentially distinct populations. Thus, it may be suggested that an exchange of virulence plasmids among strains is unlikely to occur in vivo.

Bacterial Typing Techniques↗
PubMed1995

Antimicrobial susceptibility and rRNA gene restriction patterns among Staphylococcus intermedius from healthy dogs and from dogs suffering from pyoderma or otitis externa.

A total of 60 Staphylococcus intermedius strains from dogs were investigated by their sensitivity to various antibiotics (50 strains) and by their rRNA gene restriction patterns (ribotyping) (60 strains). Fifteen isolates were from healthy dogs, 9 with otitis externa, and 36 with pyoderma, including 10 strains from a previous study. Sixty per cent of the 50 strains tested for antibiotic susceptibility demonstrated resistance to penicillin, 24% to spiramycin, 20% to tetracycline, 16% to chloramphenicol, and 2% to fucidic acid. All isolates were susceptible to amoxycillin with clavulanic acid, enrofloxacin, and sulphonamides with trimethoprim. There were no significant differences in antimicrobial susceptibility patterns observed among isolates from pyoderma, otitis externa or healthy dogs. Among the 60 strains studied by ribotyping, 10 different ribotypes were identified: 6 different ribotypes among isolates from otitis externa, 8 among isolates from pyoderma, and 5 among isolates from healthy dogs. One ribotype (profile C) was dominant among the isolates from healthy dogs while another ribotype (profile A) was dominant among strains from dogs suffering from pyoderma. This profile was not demonstrated in any of the strains from healthy dogs. From 5 different dogs suffering from pyoderma, 2 different clones were demonstrated based on their plasmid profile and antibiogram. In these dogs 1 of the clones always belonged to ribotype A. The results concerning strains of S. intermedius isolated from furunculosis suggest the existence of distinct subpopulations with different pathogenicity to dogs.

Animals↗
PubMed1995

Antibiotic resistance of Vibrio anguillarum, in relation to serovar and plasmid contents.

A total of 520 Vibrio anguillarum strains, isolated from fish and the environment, were tested for their sensitivity to 20 different antibiotics. Most isolates were of European origin. The results were compared with data on the O-serogroup and plasmid contents. All strains were sensitive to neomycin, spectinomycin, nitrofurantoin, flumequine and oxolinic acid, while most strains were sensitive to streptomycin, oxytetracycline, chloramphenicol, sulphonamides, trimethoprim, sulphonamides with trimethoprim, nalidixan, rifampicin, novobiocin and O/129. A major part of the strains were resistant to the macrolides, spiramycin and lincomycin. For ampicillin, cephalothin, and colistin marked differences were recorded with respect to O-serogroup. Most O1 strains were resistant to colistin and sensitive to ampicillin and cephalothin, while most O2 strains were sensitive to colistin but resistant to ampicillin and cephalothin. Some antibiotic resistant strains carried plasmids but no conjugation experiments were carried out to detect possible R factors.

DNA↗
PubMed1994

Double-pulse facilitation of smooth muscle alpha 1-subunit Ca2+ channels expressed in CHO cells.

Frequent strong depolarizations facilitate Ca2+ channels in various cell types by shifting their gating behavior towards mode 2, which is characterized by long openings and high probability of being open. In cardiac cells, the same type of gating behavior is potentiated by beta-adrenoceptors presumably acting via phosphorylation of a protein identical to or associated with the channel. Voltage-dependent phosphorylation has also been reported to underlie Ca2+ channel facilitation in chromaffin adrenal medulla and in skeletal muscle cells. We studied a possible voltage-dependent facilitation of the principal channel forming alpha 1-subunit of the dihydropyridine-sensitive smooth muscle Ca2+ channel. Single channel and whole-cell Ca2+ currents were recorded in Chinese hamster ovary cells stably expressing the class Cb Ca2+ channel alpha 1-subunit. Strong depolarizing voltage-clamp steps preceding the test pulse resulted in a 2- to 3-fold increase of the single Ca2+ channel activity and induction of mode 2-like gating behavior. Accordingly we observed a significant potentiation of the whole-cell current by approximately 50%. In contrast to the previous suggestions we found no experimental evidence for involvement of channel phosphorylation by protein kinases (cAMP-dependent protein kinase, protein kinase C and other protein kinases utilizing ATP gamma S) in the control and facilitated current. The data demonstrate that the L-type Ca2+ channel alpha 1-subunit solely expressed in Chinese hamster ovary cells is subject to a voltage-dependent facilitation but not to phosphorylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗