Biomedical subjects

K Hansen

Publications and source records attributed to K Hansen.

At least 127 records · Page 7Linked to original sources

PubMed1995

Unidirectional fluxes of short-chain fatty acids across segments of the large intestine in pig, sheep and pony compared with guinea pig.

Unidirectional fluxes of short-chain fatty acids across pig, sheep and pony caecum, proximal and distal colon were studied under short-circuit current conditions in Ussing chambers. Findings are compared with results from guinea pig. Marked species differences are apparent; highest mucosal-to-serosal fluxes of acetate, propionate and butyrate were seen in guinea pig, lower values in pig and smallest fluxes in sheep and pony. Segmental differences between caecum, proximal and distal colon exist mainly in guinea pig and are less developed in pig, sheep and pony. Inhibition of Na+/H+ exchange by amiloride added to the mucosal solution decreased the mucosal-to-serosal fluxes of short-chain fatty acids clearly in guinea pig caecum and proximal colon, and very little in distal colon. This effect was somewhat less pronounced in pig caecum and distal colon, in caecum and distal colon of sheep and caecum of the pony. In pig, sheep and pony proximal colon and pony distal colon no significant inhibition was observed. Inhibition of the K(+)-H+ ATPase by addition of ouabain to the mucosal solution diminished mucosal-to-serosal fluxes of short-chain fatty acids in the guinea pig distal colon extensively. No comparable inhibition was seen in any of the other segments in the animals studied.

Amiloride↗

PubMed1995

Evolution of the Borrelia burgdorferi outer surface protein OspC.

The genes coding for outer surface protein OspC from 22 Borrelia burgdorferi strains isolated from patients with Lyme borreliosis were cloned and sequenced. For reference purposes, the 16S rRNA genes from 17 of these strains were sequenced after being cloned. The deduced OspC amino acid sequences were aligned with 12 published OspC sequences and revealed the presence of 48 conserved amino acids. On the basis of the alignment, OspC could be divided into an amino-terminal relatively conserved region and a relatively variable region in the central portion. The distance tree obtained divided the ospC sequences into three groups. The first group contained ospC alleles from all (n = 13) sensu stricto strains, the second group contained ospC alleles from seven Borrelia afzelii strains, and the third group contained ospC alleles from five B. afzelii and all (n = 9) Borrelia garinii strains. The ratio of the mean number of synonymous (dS) and nonsynonymous (dN) nucleotide substitutions per site calculated for B. burgdorferi sensu stricto, B. garinii, and B. afzelii ospC alleles suggested that the polymorphism of OspC is due to positive selection favoring diversity at the amino acid level in the relatively variable region. On the basis of the comparison of 16S rRNA gene sequences, Borrelia hermsii is more closely related to B. afzelii than to B. burgdorferi sensu stricto and B. garinii. In contrast, the phylogenetic tree obtained for the B. hermsii variable major protein, Vmp33, and 18 OspC amino acid sequences suggested that Vmp33 and OspC from B. burgdorferi sensu stricto strains share a common evolutionary origin.

Amino Acid Sequence↗

PubMed1995

Comparison of in vitro culture, immunohistochemical staining, and PCR for detection of Borrelia burgdorferi in tissue from experimentally infected animals.

An avidin-biotin-amplified immunophosphatase staining method with a purified polyclonal rabbit anti-Borrelia burgdorferi hyperimmune serum was developed for identification of B. burgdorferi in tissue specimens. The diagnostic efficacy was compared with those of in vitro culture and PCR with fresh and fixed, paraffin-embedded tissues. A nested PCR assay was developed for identification of a 276-bp fragment of the B. burgdorferi flagellin gene. The diagnostic sensitivities of the different techniques were evaluated with spleen, renal, and urinary bladder tissues from eight experimentally infected gerbils. A systemic infection was verified by positivity of 23 of 24 (96%) organ cultures. B. burgdorferi was visualized immunohistochemically in 9 of 23 (39%) of the specimens. Among these nine specimens, an average of 33% of the 15 sections examined were positive. The spirochetes accumulated in discrete clusters and were associated with focal lymphocytic infiltration. The diagnostic sensitivity obtained by PCR with fixed, paraffin-embedded tissue was 21%, considerably lower than that with fresh tissue (71%). Thus, the reliable demonstration of B. burgdorferi by immunohistochemical staining is possible but extremely laborious, and considering the fact that the density of B. burgdorferi in human tissue is even lower than that in experimentally infected animals, the method is not useful in a clinical setting. It may, however, still be valuable in pathogenetic research. Detection of B. burgdorferi DNA by PCR should be performed with fresh tissue specimens and not with fixed, paraffin-embedded specimens.

Animals↗

PubMed1995

Long-term effects of the Herbst appliance on the dental arches and arch relationships: a biometric study.

The purpose of this study was to evaluate biometrically the treatment and post-treatment effects of the Herbst appliance on the dental arches and arch relationships. The sample consisted of 53 Class II, division 1 malocclusion patients (33 boys and 20 girls) treated with the Herbst appliance. The mean age of the patients before treatment was 12.5 years (SD = 1.2 years). Dental casts were analysed before treatment, after treatment, 6 months post-treatment and at the end of the growth period (5-10 years post-treatment). The following variables were assessed: sagittal molar and canine relationships, overjet, overbite, maxillary and mandibular arch perimeters, and inter-molar and inter-canine dental arch widths. During treatment, the overjet, overbite, and sagittal molar relationship were overcorrected in most of the cases, while the sagittal canine relationship was normalized. The maxillary and mandibular arch perimeters increased during treatment, as did dental arch widths (molar and canine). In the long-term (mean = 6.7 years after treatment), Herbst appliance treatment resulted in a normal or over-corrected sagittal molar relationship in 79 per cent and a normal canine relationship in 68 per cent of the cases. Eighty-three per cent of the subjects had an overjet of 4.5 mm or less. In the long-term, the arch perimeters seemed to follow a normal dental development pattern. The increase of the upper molar and canine dental arch widths during treatment remained virtually stable whilst the lower intermolar arch widths seemed unaffected by treatment.

Adolescent↗

PubMed1994

Stable expression of a functional GluR6 homomeric glutamate receptor channel in mammalian cells.

This study demonstrates the stable expression of a functional ionotropic glutamate receptor in a mammalian cell line of non-neuronal origin. The kainate-selective glutamate receptor GluR6 was constitutively expressed under the control of a metallothionein promoter. Clones were isolated expressing approximately 3 pmol of receptor per mg of protein. Functionality of the recombinant GluR6 was demonstrated both by electrophysiology and by Ca2+ imaging. Application of kainate to the GluR6-transfected cells activated an inward current response at a holding potential of -60 mV. The kainate concentration needed to evoke 50% of the maximal response (EC50) was calculated to be 0.82 +/- 0.39 microM. The current-voltage relationship was found to be almost linear, with a reversal potential of -2.5 +/- 4.8 mV. Application of kainate also resulted in an increase in the intracellular Ca2+ concentration measured by Ca2+ imaging. The pharmacological profile of [3H]kainate binding to the recombinant GluR6 resembled the high-affinity [3H]kainate binding sites in rat brain, showing high affinity for domoate (Ki = 5.1 +/- 3.0 nM) and kainate (Kd = 12.9 +/- 2.4 nM). No decrease in GluR6 expression level was observed over > 75 passages of the transfected cells. When domoate, a slowly desensitizing GluR6 agonist, was included in the growth medium for 3 weeks, the number of GluR6 binding sites decreased by 30%, indicating the importance of complete channel closure for stable expression.

Animals↗

PubMed1994

[Laser therapy of Achilles tendinitis].

The effects of low level laser treatment in soldiers with achilles tendinitis were studied in a prospective, randomized and double blind trial. Eighty-nine soldiers were enrolled in the study. Forty-six were randomized to treatment with active laser and 43 to treatment with placebo laser. No statistically significant differences in the number of consultations, morning stiffness, tenderness, crepitation, swelling, redness, VAS-score of pain and degree of unfitness for duty were found between the two treatment groups.

Achilles Tendon↗

PubMed1994

Functional role of bicarbonate in propionate transport across guinea-pig isolated caecum and proximal colon.

1. Unidirectional fluxes of propionate across isolated epithelia from the guinea-pig caecum and proximal colon were measured under short-circuit current conditions. In the caecum and proximal colon the serosal-to-mucosal propionate flux (JPrsm) was higher than mucosal-to-serosal flux (JPrms), resulting in a net secretory flux of propionate. 2. HCO3(-)-CO2-free solution reduced JPrms in the caecum and proximal colon markedly; JPrsm was not (caecum) or little (proximal colon) affected. The subsequent addition of acetazolamide caused a further decrease in JPrms in the proximal colon, but not in the caecum. 3. In HCO3(-)-containing solutions acetazolamide or ethoxzolamide inhibited JPrms; JPrsm was not affected. A macromolecular carbonic anhydrase inhibitor, prontosil-dextran, had no effect on propionate fluxes, indicating that the intracellular carbonic anhydrase is of importance for short-chain fatty acid transport. 4. Subsequent to carbonic anhydrase inhibition, mucosal addition of amiloride caused a slight further decrease of JPrms in the caecum and proximal colon; JPrsm was not affected. 5. Results support the view that a considerable proportion of short-chain fatty acids (SCFAs) is absorbed via a SCFA(-)-HCO3- exchange.

Acetazolamide↗

PubMed1994

Direct interaction between Shc and the platelet-derived growth factor beta-receptor.

The Src homology 2 (SH2) domain-containing Shc proteins p52shc and p46shc become phosphorylated upon activation of several tyrosine kinases and are implicated in mitogenic signal transduction. Ligand stimulation of the platelet-derived growth factor (PDGF) beta-receptor leads to autophosphorylation of tyrosine residues, which is known to mediate interactions with several SH2 domain-containing signaling molecules. In this study, we have characterized the interaction between the PDGF beta-receptor and Shc. PDGF beta-receptor coprecipitation in Shc immunoprecipitates was dependent on stimulation with PDGF-BB. The Shc SH2 domain expressed as a bacterial fusion protein bound the autophosphorylated PDGF beta-receptor. Moreover, the Shc SH2 domain could bind the autophosphorylated purified baculovirus-expressed PDGF beta-receptor intracellular domain, which indicates a direct association of Shc with the PDGF beta-receptor. Activation of the PDGF beta-receptor induced the preferential phosphorylation of p52shc. Tyrosine-phosphorylated Shc, in turn, formed a complex with the signaling molecule Grb2. Synthetic peptide analysis revealed that certain autophosphorylation sites in the PDGF beta-receptor (Tyr-579, Tyr-740, Tyr-751, and Tyr-771) were able to mediate the specific binding of the Shc SH2 domain as well as intact Shc proteins. A mutant PDGF beta-receptor in which Tyr-579 was replaced with phenylalanine showed 40% impaired association of Shc in vivo, but phosphorylation of Shc proteins was not affected. We conclude that multiple autophosphorylation sites in the PDGF beta-receptor are responsible for the binding of Shc. This is in contrast to previously characterized interactions between the PDGF beta-receptor and SH2 domain-containing proteins, which generally involve one high affinity binding site in the receptor.

Adaptor Proteins, Signal Transducing↗

PubMed1994

Taxonomic classification of 29 Borrelia burgdorferi strains isolated from patients with Lyme borreliosis: a comparison of five different phenotypic and genotypic typing schemes.

Twenty-nine European and North American Borrelia burgdorferi strains isolated from patients with Lyme borreliosis, were investigated by restriction fragment length polymorphism (RFLP) of two phylogenetically highly conserved chromosomal genes encoding flagellin (fla) and the p60 common antigen (CA), as well as of the plasmid-borne outer surface protein A (ospA) gene. RFLP of the ospA, fla and CA gene revealed five, two and four distinct subspecies-specific patterns, respectively. RFLP classification of the B. burgdorferi strains was compared with four different classification schemes proposed by others: (i) molecular mass profile of OspA and OspB (Adam et al. [1]); (ii) OspA serotyping (Wilske et al. [34]); (iii) genomic fingerprinting on the central region of the B. burgdorferi fla gene (Picken [24]) and (iv) 16S rRNA signature nucleotide analysis (Marconi and Garon [19]). Results obtained with the different methods correlated highly. All strains classified as B. burgdorferi sensu stricto and B. afzelii could be unequivocally identified as one distinct group by all five typing methods. B. garinii isolates, however, were more heterogeneous and according to RFLP of the CA and ospA gene fell into either two or three subgroups. The agreement of the different approaches supports the recent concept that B. burgdorferi sensu lato strains should be delineated to three genomic groups and that B. burgdorferi sensu lato is clonal. All 12 US strains were B. burgdorferi sensu stricto, whereas the 17 European isolates belonged to any of three genospecies. Among European B. burgdorferi isolates there was an association between B. burgforferi genospecies and the clinical manifestation of Lyme borreliosis. B. afzelii strains were found to predominate in 11 skin isolates (75%), whereas all 6 cerebrospinal fluid isolates from patients with neuroborreliosis were B. garinii. These findings support the concept of a strain-dependent organotropism of B. burgdorferi.

Animals↗

PubMed1994

Cholinergic potentiation of the meal-related rise in ACTH and cortisol concentrations in men.

The present study examined the influence of physostigmine, an acetylcholine esterase inhibitor, on the secretory activity of the hypothalamo-pituitary-adrenocortical (HPA)--axis under basal (experiment I) and stimulated (experiment II) conditions in young healthy men. In a third experiment, the effect of scopolamine, a muscarinic acetylcholine receptor antagonist, on HPA secretory activity after physiological stimulation was tested. The experiments started between 09.00 and 10.00 a.m.. After a resting period of 1.5 h, either physostigmine (0.0125 mg per kg body weight soluted in isotonic saline) or placebo (saline) was infused within 15 min. In experiment I subjects (n = 7) remained fasting while in experiment II (n = 18) a standardized lunch was offered after the infusion. Experiment III (n = 7) was designed as experiment II but instead of physostigmine, scopolamine or placebo (0.5 mg) was subcutaneously injected 105 min before the meal. Blood for the determination of ACTH and cortisol was drawn in regular intervals during the experiments. Physostigmine did not change basal ACTH and cortisol secretion per se, excluding activation of basal HPA secretion due to acetylcholineesterase inhibition and its non specific side effects. Meal intake stimulated ACTH and cortisol secretion which was significantly enhanced when physostigmine was administered (p < 0.05). Scopolamine did not influence the meal related ACTH and cortisol secretion. These findings demonstrate that cholinergic neurotransmission is able to increase ACTH and cortisol concentrations in humans. This effect seems to be complementary to other stimulatory neurotransmitter systems, and is functional during stimulated HPA secretory activity and not under basal conditions.

Adrenocorticotropic Hormone↗

PubMed1994

Low back pain in steelplant workers.

The association between low back pain and occupational work loads, lifestyle factors and socio-demographic factors was examined in 469 steelplant workers (436 men, 33 women), aged 40 +/- 12 years (mean +/- SD). Fifty-one per cent had experienced low back pain during the preceding year. The strongest associations were found between recent low back pain and domestic recreational activities (> or = 3 h/week vs. 0-2 h/week), and between recent low back pain and work pace (too fast vs. adequate), with odds ratios (95% confidence limits) of 3.0 (1.5-5.8) and 2.3 (1.2-4.2), respectively. We considered a subject to have a particularly severe history of low back pain if, due to low back trouble, he (i) had ever been admitted to a hospital, (ii) had ever had to change work, or (iii) had had more than one week's accumulated sick leave during the preceding year. There was a strong association between a severe low back pain history and lifetime occupational exposure to heavy and frequent lifting at work. Forty-seven per cent of severe low back pain events could be ascribed to heavy and frequent lifting, assuming the associations were causal. We conclude that domestic recreational activities may be an important potential confounder in studies on occupational risk factors for low back pain, and that, based on the results of this and of other studies, a case for prevention still seems to exist regarding lifting of heavy burdens in the work environment.

Adult↗

PubMed1994

Performance of four different indirect enzyme-linked immunosorbent assays (ELISAs) to detect specific IgG, IgA, and IgM in Legionnaires' disease.

Currently recommended methods in Legionnaires' disease serology are based upon crude whole-cell antigenic preparations. To investigate whether purified antigens would perform better in a given diagnostic test for antibodies against Legionella pneumophila, we compared the performance of three antigenic preparations of L. pneumophila serogroup 1 consisting of outer membrane protein (OMP), flagellin (FLA), and lipopolysaccharide (LPS) to a sonic extract (SON) in indirect immunosorbent assay (ELISA) measuring both IgG, IgA, and IgM. The reactivity of sera from 20 patients with culture-verified Legionnaires' disease and sera from 12 patients with pneumonia and a diagnostic rise in titre by a microagglutination test (MA) was studied. Our results indicated that the SON IgA assay was the most sensitive test in both groups of patients. The LPS IgG and IgM assays, however, were the most specific tests, closely followed by the corresponding SON tests. By combining two individual assays, a maximum nosographic sensitivity of 85% could be obtained. Whereas no benefit of using purified outer membrane protein or flagella instead of a sonic extract in the indirect ELISAs was found, the LPS antigen provided a sensitive and specific alternative to the sonic extract.

Antibodies, Bacterial↗

PubMed1994

Serological follow-up after treatment of patients with erythema migrans and neuroborreliosis.

To investigate the duration and kinetics of immunoglobulin M (IgM) and IgG antibodies against Borrelia burgdorferi in serum after treatment of Lyme borreliosis, consecutive serum samples from 30 seropositive patients with erythema migrans and 91 seropositive patients with neuroborreliosis were analyzed with a capture IgM enzyme-linked immunosorbent assay (ELISA) and an indirect IgG ELISA, both using B. burgdorferi flagella as the antigen. All the patients improved after treatment: 97 patients had a complete clinical recovery, while 24 patients had sequelae. The results showed that patients with erythema migrans and early neuroborreliosis more often initially had highly elevated IgM optical density (OD) values and low IgG OD values against B. burgdorferi, while the opposite was found in patients with late neuroborreliosis. During follow-up, the majority of patients had developed negative or significantly declining IgM ODs after 1 to 1.5 years but persistently positive IgM ODs were found up to 17 months after treatment of erythema migrans and 3 years after treatment of neuroborreliosis. IgG antibody levels declined more slowly and remained elevated to a larger extent, but more than half of the patients had developed negative IgG ODs within 5 years after therapy. However, positive IgG OD values were found after 9 to 10 years for patients treated for neuroborreliosis as well as erythema migrans. Both IgM and IgG antibodies against B. burgdorferi may persist for months to years after successful treatment of Lyme borreliosis. Consequently, a single serum sample with antibodies against B. burgdorferi must always be carefully evaluated and correlated to clinical symptoms.

Adult↗

PubMed1994

Natural killer cell activity in early human pregnancy.

Natural killer (NK) cell activity was determined in 41 women during the first trimester of pregnancy. NK cytotoxicity was similar between the study subjects and nonpregnant controls and was not a reflection of a change in the circulating number of cells or density in culture. Although NK cells may play a role in maternal immune status in advanced pregnancy, NK cells do not appear to be crucially involved in the first trimester, when reproductive wastage usually occurs.

Cytotoxicity, Immunologic↗

PubMed1994

Serological follow-up after treatment of Borrelia arthritis and acrodermatitis chronica atrophicans.

To study the serological response to Borrelia burgdorferi after treatment of late Lyme borreliosis, consecutive serum samples from 20 patients with Borrelia arthritis and 21 with acrodermatitis chronica atrophicans were analysed with capture IgM ELISA and indirect IgG ELISA, both using B. burgdorferi flagella as antigen. Seven patients had positive IgM OD values, whereas all 41 had positive IgG OD values before therapy. In the majority, highly elevated IgG OD values were seen. All patients improved after antibiotic therapy, 32 recovering completely, while 9 had sequelae. At follow-up after 6 months to 5 years, 4/7 patients became negative IgM ELISA, whereas 3 still had slightly elevated IgM OD values 6 months, 1 year and 4.5 years, respectively, after therapy. Only one patient became negative in IgG ELISA during follow-up, although a significant decline in IgG OD values was seen in 22 of the remaining 40 initially IgG-positive patients. The serological response after successful treatment of Borrelia arthritis and acrodermatitis chronica atrophicans may persist for several years even with highly elevated IgG OD values in patients who have recovered completely.

Acrodermatitis↗

PubMed1994

Cytogenetics in the diagnosis of hematologic malignancies.

Practical uses of cytogenetic analysis in hematopoietic disorders include the following: confirm/establish a diagnosis of chronic myelocytic leukemia (CML) confirm/predict blast crisis of CML help in diagnosis/prognosis of acute leukemia confirm/establish remission or relapse in acute leukemia help in diagnosis/prognosis of myelodysplastic states evaluate post-bone marrow transplant recipients help in diagnosis of some lymphoproliferative disorders aid researchers in discovery of critical gene loci that may eventually result in more effective treatment. Cytogenetic laboratories and molecular genetic laboratories should be in close communication to recommend the most appropriate studies in any given case and to avoid expensive duplication of work.

Cytogenetics↗

PubMed1994

Use of a gonadotropin releasing hormone agonist before vaginal surgery for cervical leiomyomas. A report of two cases.

Two cases of cervical myoma were treated with combined medical/surgical therapy using a gonadotropin releasing hormone agonist (GnRH-a) and transvaginal cervical myomectomy. Patients were treated with depot GnRH-a (leuprolide acetate) for two months followed by myomectomy. This approach allowed successful treatment with short hospitalization (< 24 hours). Potential benefits of this regimen include decreased intraoperative blood loss, outpatient management, decreased morbidity, decreased hospital expense and preservation of reproductive potential by avoiding hysterectomy.

Adult↗

PubMed1994

Lyme neuroborreliosis: improvements of the laboratory diagnosis and a survey of epidemiological and clinical features in Denmark 1985-1990.

Lyme neuroborreliosis (LNB) has within the last few years become one of the most frequent neuroinfections. This thesis is based on 7 publications which have two main topics: (i) to improve and develop laboratory methods for routine diagnosis of LNB, (ii) to generate epidemiological data for LNB and to achieve a descriptive clinical delimitation of this disease. Laboratory diagnosis in Lyme borreliosis is based on detection of a Borrelia burgdorferi (Bb) specific immune response. Up till now serological assays have not achieved a sufficient diagnostic specificity and sensitivity. This is partly due to the use of test antigens consisting of all proteins of the spirochete including broadly cross-reacting antigens. In order to improve diagnostic antibody detection we isolated an immunodominant structural protein of Bb, the motility organelle the flagellum. The use of native, morphologically intact flagella as test antigen in ELISA led to a significantly increased diagnostic specificity, and, especially in early disease, to an improved diagnostic sensitivity. Reservations regarding the use of only one out of the over 100 proteins of Bb as a diagnostic antigen probe are groundless. The early as well as the late immune response to Bb always includes antibodies to the flagellum. The Bb flagellum is as a test antigen not completely Bb specific. Compared with all other antigen preparations however, the flagellum is at present the best compromise, if a sensitive and specific routine serology is requested. The diagnostic performance of specific IgM detection was improved with a mu-capture ELISA, which used biotin labelled Bb flagella. Compared to conventional indirect ELISA this technique avoids false positive results due to IgM rheumatoid factor interference and false low or false negative results due to IgG competition for the test antigen. The antibody response in Bb infection develops slowly. Patients with LNB can be antibody negative in blood up to 6-8 weeks after onset of neurological symptoms. Longstanding but seronegative disease in untreated patients is unlikely to occur. Expectations of further improvement of Lyme borreliosis serology focuses presently on the performance of the outer surface protein (Osp) C as a test antigen and on the genus specific domain of the Bb flagellin. Theoretically this region constitutes the best candidate for a better test antigen either as a recombinant or a synthetic peptide. In LNB a prominent Bb specific intrathecal antibody response develops.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗