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H Auer

Publications and source records attributed to H Auer.

At least 19 recordsLinked to original sources
PubMed2004

Pressure-induced hole doping of the Hg-based cuprate superconductors.

We investigate the electronic structure and the hole content in the copper-oxygen planes of Hg-based high T(c) cuprates for one to four CuO2 layers and hydrostatic pressures up to 15 GPa. We find that with the pressure-induced additional number of holes of the order of 0.05e the density of states at the Fermi level changes by approximately a factor of 2. At the same time, the saddle point is moved to the Fermi level accompanied by an enhanced k(z) dispersion. This finding explains the pressure behavior of T(c) and leads to the conclusion that the applicability of the van Hove scenario is restricted. By comparison with experiment, we estimate the coupling constant to be of the order of 1, ruling out the weak coupling limit.

Journal Article↗
PubMed2004

Echinococcus granulosus strain differentiation based on sequence heterogeneity in mitochondrial genes of cytochrome c oxidase-1 and NADH dehydrogenase-1.

Genetic analyses of Echinococcus granulosus isolates from different intermediate host species have demonstrated substantial levels of variation for some genotype (strain) clusters. To determine the range of genetic variability within and between genotypes we amplified and cloned partial cox1 and nadh1 genes from 16 isolates of E. granulosus from 4 continents. Furthermore, we sequenced different clones from a PCR product to analyse the intra-individual genetic variance. The findings showed a moderate degree of variance within single isolates and a significant degree of variance between the cluster of genotypes G1-G3 (sheep, Tasmanian sheep and buffalo strain), genotypes G4 (horse strain) and G5 (cattle strain) and the cluster of the genotypes G6 (camel strain) and G7 (pig strain). The variance of up to 2.2% within genotypes was relatively low compared with that of 4.3-15.7% among genotypes. The present results indicate that a re-examination of the classification of 5 genotypes of Echinococcus is warranted. Hence, our data highly support a re-evaluation of the taxonomy of the clades G1-G3, G4, G5, G6/7 and G8 (cervid strain) within the genus Echinococcus.

Animals↗
PubMed2003

Analysis of the sensitization profile towards allergens in central Africa.

BACKGROUND: Almost no information is available regarding the prevalence of IgE-mediated allergies and the disease-eliciting allergens in tropical Africa. OBJECTIVE: To study IgE-mediated allergies and the allergen profile in allergic patients from Zimbabwe. METHODS: The frequency of sensitization to common environmental allergen sources was determined by skin prick testing in 650 allergic patients from Zimbabwe. Fifty representative sera were analysed for IgE reactivity to 20 respiratory and 20 food allergen extracts by multiallergen extract testing. The IgE reactivity profiles to recombinant pollen and mite allergens were compared between grass pollen- and mite-sensitized patients from Zimbabwe and central Europe. Sera from grass pollen-allergic patients were also analysed for IgE reactivity to nitrocellulose-blotted natural timothy grass and Bermuda grass pollen allergens. RESULTS: IgE-mediated allergies were found to be common in Zimbabwe. Similar to the situation in central Europe, mites and grass pollens represented the most prevalent allergen sources. However, the IgE reactivity profiles determined with single recombinant pollen and mite allergens revealed interesting differences between the European and African patients, which most likely reflect the local allergen exposure. CONCLUSIONS: The striking differences regarding sensitization to grass pollen and mite allergens between African and European patients revealed by recombinant allergen-based testing emphasize the need for component-resolved allergy testing to optimize allergy prevention and therapy in different populations.

Adolescent↗
PubMed2001

Recombinant dissection of myosin heavy chain of Toxocara canis shows strong clustering of antigenic regions.

Myosins from nematode parasites elicit strong humoral and cellular immune responses and have been investigated as vaccine candidates. In this study we cloned and sequenced a cDNA coding for myosin heavy chain from Toxocara canis, a nematode parasite of canids which may also infect humans and cause various unspecific symptoms. To determine the major antigenic regions the myosin heavy chain was systematically dissected into ten overlapping recombinant fusion polypeptides which were purified by metal chelate chromatography. Single fragments were then tested for their IgG reactivity in sera from toxocarosis patients and healthy probands. Two regions, one region at the mid to carboxy-terminal end of the head domain and one region in the rod domain, were identified as major antigens, which in combination were positive with 86% of the sera. The other domains were less reactive. This shows that the patients' IgG reactivity was not directed evenly against all parts of the molecule, but was rather clustered in few regions.

Amino Acid Sequence↗
PubMed2001

Allogeneic bone marrow transplantation-mediated transfer of specific immunity against Toxocara canis associated with excessive IgE.

A girl with myelodysplastic syndrome (RAEB-T) received HLA-identical bone marrow from her younger brother after myeloablative treatment with busulfan and cyclophosphamide. After bone marrow transplantation, fever, exanthema, pruritus, and a pulmonary infiltrate were treated symptomatically. Bacterial cultures remained negative. Leukocyte engraftment began on day 10, and all blood cell populations proved to be of donor origin on FISH analysis. Increasing IgE levels (21 000 U/ml) on day 14 after BMT, positive RAST, specific IgG-antibodies, and missing Toxocara (T.) canis antigens in the recipient indicated donor-derived seroconversion. Before BMT, the recipient had been negative for T. canis in routine parasitological screening, and the donor proved to be positive for T. canis antibody by ELISA. This report suggests that the transfer of IgE immunity in the absence of detectable antigens may be responsible for IgE-mediated symptoms consistent with toxocara infection and confirms the need for parasite screening in donor medical examinations.

Adoptive Transfer↗
PubMed2001

Treatment of ocular toxocariasis with albendazole.

The purpose of this study was to evaluate the efficacy of combined albendazole and steroid treatment for uveitis caused by Toxocara canis in immunocompetent patients. Five patients (7 eyes) with ocular larva migrans syndrome (OLM) were used in this study. Toxocariasis was suspected based on clinical manifestations and confirmed by anti-toxocara IgG and Western blot analysis. Systemic albendazole (adults: 800 mg b.i.d.; children: 400 mg b.i.d.) was given in conjunction with steroids. Visual acuity before and after therapy, inflammatory response, side effects and toxicity were evaluated. Treatment resulted in an improved visual acuity in all patients. Mean initial Snellen visual acuity was 20/40, and mean final acuity was 20/20. There were no recurrences of uveitis throughout the observation period (average: 13.8 months; range: 3 days to 24 months). These findings suggest that albendazole, in combination with systemic steroids, is a useful regimen to treat ocular larva migrans syndrome.

Adolescent↗
PubMed2000

[Toxocara and bronchial hyperreactivity--results of a seroprevalence study].

For more than 30 years the ascarid Toxocara canis, a parasite of the dog, has been considered a possible cause of allergic-pulmonal irritations (i.e. asthma bronchial) in man. According to a British study thousands of people are presumably suffering from asthma bronchial as a consequence of Toxocara infestations. The aim of our recent study was the assessment of the Toxocara seroprevalence in patients of varying bronchial reactivity and status of atopy suffering from respiratory disturbances. 191 serum samples from 59 male (mean age: 31.7 years) and 132 female patients (mean age: 36.6 years) with varying atopy status and degree of bronchial reactivity, living in or near Vienna, were examined for specific IgG antibodies against excretory-secretory (E/S) Toxocara canis antigen with enzyme-linked immunosorbent assay (TES-ELISA) and Western blot (TES-WB). In total a Toxocara seroprevalence of 9.4% could be assessed among these patients. 10% of the patients with and 7.8% of the patients without bronchial hyperreactivity were Toxocara-positive. Atopic patients were serologically positive in 7.1% of the cases tested whereas non-atopics showed an antibody prevalence of 14.3%. A comparison of Toxocara seroprevalence assessed within the recent study and in an earlier study among healthy pregnant women in Vienna did not show significant differences. The results of this study carried out in Vienna indicate that patients with bronchial hyper-reactivity or atopy show no higher seroprevalence than the normal population.

Adolescent↗
PubMed2000

Clinical and diagnostic relevance of the Toxoplasma IgG avidity test in the serological surveillance of pregnant women in Austria.

For evaluation of the medical relevance of a Toxoplasma IgG avidity test within the Austrian program for screening of pregnant women, 23 sera from women with seroconversions (group 1) and with proven latent Toxoplasma infections (group 3), respectively, as well as 92 sera from women suspected of having a primary infection (group 2) were tested by the indirect immunofluorescence test (IFAT), Sabin-Feldman's dye test (SFT), IgM enzyme-linked immunofluorescence assay (ELFA-IgM), IgA microparticle enzyme immunoassay, and the IgG avidity test. Group 1 sera (seroconversions) revealed a median avidity index (AI) of 0.25, whereas the median AI of group 3 sera (latent infections) was 0.66. In 31 (33.7%) of 92 cases suspected of involving a primary Toxoplasma infection, low (<0.41) or borderline AIs (0.41-0.50) were assessed, and in 61 cases (66.3%) the AIs exceeded 0.50. Finally, a recent infection could be excluded due to the results of the IgG avidity test in 59 cases; in at least 34 IgM-positive cases an unnecessary and, thus, unjustified treatment could be avoided.

Animals↗
PubMed2000

Radical surgical therapy of abdominal cystic hydatid disease: factors of recurrence.

A series of 74 consecutive patients (48 women, 26 men) were operated for abdominal hydatid disease between June 1949 and December 1995. The patients ranged in age from 15 to 81 years (median 49 years). In 69 cases only the liver was affected; two patients had concomitant extrahepatic disease (one spleen, one spleen and lung), and 3 had cysts in the spleen only. Cysts were multiple in 11 patients and calcified in 24. Conservative surgical procedures were used for 22 cysts in 20 patients [open partial (n = 3), open total (n = 6), closed total cystectomy (n = 9), marsupialization (n = 2), drainage (n = 2)] and radical surgical procedures for 72 cysts in 54 patients [pericystectomy (n = 41), wedge liver resection or hemihepatectomy (n = 25), splenectomy (n = 5), radical resection of a lung cyst (n = 1)]. Altogether 37 patients (50%) were given perioperative antihelmintic chemotherapy with mebendazole (18 patients) or albendazole (19 patients). Operative mortality rates were 5.0% after conservative surgery and 1.8% after radical surgery. Morbidity rates were 25.0% following conservative surgery and 24.1% following radical surgery. Antihelmintic therapy was well tolerated by all but five patients. All side effects were entirely reversible. Among the 74 patients, 60 (81.0%) were available for long-term follow-up (median 7.2 years; range 2.0-47.0 years). Recurrence of disease was seen in 9 of 60 patients at an interval of 3 months to 20 years from the first operation. The rate of recurrence was significantly lower after radical surgical procedures (p = 0.03) and after closed removal of the cyst (p = 0.04).

Adolescent↗
PubMed2000

Valve repair in mitral regurgitation complicated by severe annulus calcification.

BACKGROUND: Valvuloplasty has significant advantages over valve replacement for mitral regurgitation, but the presence of severe calcification of the mitral valve apparatus has been thought to preclude successful valve reconstruction in general. The purpose of this report is to assess the results of valvuloplasty in patients with severe mitral regurgitation having extensive calcification extending from the mitral annulus to underlying myocardium and parts of the papillary muscles. METHODS: Thirty-seven adult patients with severe mitral regurgitation and calcification were operated on between April 1990 and January 1998. Twenty-six patients had degenerative disease, 4 had acute bacterial endocarditis, 6 had postrheumatic fever, and 1 patient had Marfan's disease. The valve repair comprised of en bloc decalcification with extensive leaflet debridement and reconstruction of the annulus. Autologous pericardium was used in patch-extended endocardial annuloplasty or leaflet repair. Valve competence was retained after correction of regurgitation by sliding atrioplasty, rotation paracommissural sliding plasty, cusp remodeling, or chordal repair. All patients required a prosthetic annuloplasty. RESULTS: Follow-up echocardiography at 47 months (range, 3 to 92 months) showed no or only trivial mitral regurgitation in 33 patients; 3 had grade I-II mitral regurgitation and 1 required valve replacement after 3 months. Freedom of reoperation at 1 and 5 years was 94.6%. At last examination, 33 patients were in New York Heart Association functional class I and 3 in class I-II; there has been no mortality and no thromboembolic events. CONCLUSIONS: Valvuloplasty can be safely and successfully carried out in patients suffering from regurgitation associated with severe calcification of the mitral apparatus. With encouraging beneficial midterm results, we suggest patients with calcified valves should not be excluded from mitral repair.

Adult↗
PubMed2000

Serological detection of Capillaria hepatica by indirect immunofluorescence assay.

In this paper, a serological assay for the detection of antibodies to Capillaria hepatica, a zoonotic parasite, is described. In the past, the only way of detecting Capillaria hepatica was to perform a liver biopsy. The indirect immunofluorescence (IIF) assay, based on liver sections of naturally infected mice and human serum samples, is suitable for detecting early stages of human infections and for screening purposes. No cross-reactivity with other parasitic infections was detected. We have applied the IIF assay to serum samples of 60 employees of the Zoological Garden of Vienna, Schönbrunn, Austria, and found one positive and one questionable sample.

Animals↗
PubMed1999

Pulmonary echinococcosis (hydatidosis) in children: results of surgical treatment.

From 1986-1996, 33 children with 49 pulmonary hydatid cysts underwent surgical treatment in Vienna and Istanbul. Cysts were unilateral in 28 and bilateral in 5 cases; unruptured cysts (URC) were diagnosed in 19 patients, and 14 children presented with ruptured cysts (RC). Ten patients had cysts in other organs (liver, spleen, central nervous system) in addition to pulmonary cysts. Diagnosis was primarily based on chest X-ray and computed tomography scan. In Austrian children, a new combination of serological tests was used successfully (71% positive). The standard surgical procedure was cystotomy followed by capitonnage. The main postoperative complications were fever and wound infection. There were two recurrences after a mean follow-up of 4.8 years, and one patient died because of multiple organ involvement. We conclude that the therapy of choice in pediatric pulmonary hydatidosis is complete surgical elimination of the cyst by cystotomy and capitonnage, whereas more extended resections should be avoided. Ideally, benzimidazole treatment should be combined with surgery. New serological tests can improve diagnostic accuracy.

Adolescent↗
PubMed1999

Spatial structures of the bradykinin potentiating peptide F from Agkistrodon piscivorus piscivoris venom.

Bradykinin potentiating peptides usually show two different activities, potentiation of bradykinin and inhibition of angiotensin converting enzyme (ACE). Exceptions of this rule have been found suggesting that both effects occur independently. This study of peptide F by means of NMR spectroscopy shows clearly two different main conformations of the molecule. These different conformations may be the reason for the different activities.

Agkistrodon↗
PubMed1999

Experimental investigations on the B and T cell immune response in primary alveolar echinococcosis.

Susceptibility/resistance of the intermediate host to alveolar echinococcosis (AE) seems to be based on hitherto unknown immunological mechanisms, possibly involving the activation of different CD4+ T cell immune responses (Th1/Th2). Mice of two strains previously characterized as 'susceptible' (C57BL/6 J) and 'resistant' (C57BL/10 J) to secondary AE were orally infected with eggs of Echinococcus multilocularis and the course of infection was analysed by macroscopical, pathohistological and immunohistochemical examinations of the lymphocytes and cytokines participating in the periparasitic granulomas and by serological examinations of cytokines and E. multilocularis-specific antibodies. Although differences in the extent of parasitic growth were seen between the two groups, the composition of the granulomas was quite similar with CD4+ cells being the dominant lymphocyte subpopulation, succeeded by B cells and CD8+ cells. Interferon (IFN)-gamma-, interleukin (IL)-2- and IL-4-expressing cells could not be detected in the lesions of the early phase of the infection, possibly indicating the host's immunosuppression, but were present at the end. IL-10 was the most prominent cytokine throughout the course of the disease. Serological analyses of the cytokine concentrations revealed small amounts at the beginning and high levels at the end of the infection. The pattern of cytokine response was similar for IL-4 in both strains, but different for IL-2 and IL-10 in the late phase, when the C57BL/10 J strain developed higher levels than the C57BL/6 J strain. Correspondingly only small amounts of immunoglobulin (Ig)M, IgG1, IgG2a and IgG3 could be detected at the beginning of disease, followed by higher levels at the end. The courses of antibody titres were similar in both groups except IgG3, which was more pronounced in the C57BL/10 J strain. Parasite-specific IgG2b could neither be detected in the C57BL/6 J nor in the C57BL/10 J strain by the test system used. The results of the study suggest both subsets of CD4+ T cells (Th1 and Th2) being involved in murine primary alveolar echinococcosis. A strict differentiation of mice in susceptible and resistant animals based on the activation of different CD4+ T cell immune responses (Th1 'resistant' and Th2 'susceptible') should be avoided.

Animals↗
PubMed1999

Variations of p53 in cultured fibroblasts of patients with lung cancer who have a presumed genetic predisposition.

The authors studied cultured skin fibroblasts of 64 patients with lung cancer for constitutive mutations of the p53 tumor suppressor gene by using polymerase chain reaction and single-strand conformation polymorphism covering the entire coding region. The patients were considered to be genetically predisposed because lung cancer had developed in 25 of them before age 46 and because 42 of them had at least one first-degree relative with lung cancer. One mutation was detected at position 235 coding for serine instead of asparagine in the conserved DNA binding domain. The Pro/Pro genotype at codon 72 of p53, considered to harbor an increased risk for lung cancer, could not be detected with increased frequency in this study's patients. From these data, the authors conclude that constitutive variations of the p53 gene do not represent a major genetic determinant for lung cancer.

Adult↗
PubMed1998

[Ocular toxocariasis in Austria].

HISTORY AND CLINICAL FINDINGS: Two women (aged 21 and 44 years) were referred because of a suspect retinal lesion. An ophthalmological examination in both revealed prominent retinal granulomatous foci, probably ocular toxocariasis. Both women were otherwise well; both reported close contact with dogs. INVESTIGATIONS: Among a full array of laboratory tests the only major pathologic findings were high antibody titres against Toxocara canis (patient 1: 70 antibody units [AU]; patient 2: > 100 AU), specific antibodies in the ELISA and Western blot tests confirming the diagnosis of T. canis infection. DIAGNOSIS, TREATMENT AND COURSE: Both patients were treated with prednisolone (initially 75 mg/d, gradually decreasing over 4 months) and albendazole (2 x 800 mg/d for 6 days), with complete healing of the chorioretinal foci. CONCLUSION: General physicians as well as ophthalmologists should more often include Toxocara canis infection in the differential diagnosis, because the larvae, in their migration through the body, can infest various organs where they can cause inflammatory or allergic reactions.

Adult↗