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R Berner

Publications and source records attributed to R Berner.

52 records · Page 3Linked to original sources
PubMed1994

Desferrioxamine-promoted virulence of Yersinia enterocolitica in mice depends on both desferrioxamine type and mouse strain.

The effects of desferrioxamine B (DFOB) and G (DFOG) on growth promotion and virulence of Yersinia enterocolitica as well as on T cell activation and proliferation were investigated. Both desferrioxamines promoted growth of Y. enterocolitica O:8 (WA-314) and O:3 (Y-108). DFOB had a greater immunosuppressive effect on T cells than did DFOG. These results suggest a dual role of DFOB in yersiniosis: growth promotion of the pathogen and immunosuppression of the host. The LD50 of both Yersinia strains for mice was reduced by DFOB but not by DFOG. However, the LD50 of yersiniae was reduced by DFOB to a greater extent in Yersinia-resistant C57BL/6 than in Yersinia-susceptible BALB/c mice. The different impact of DFOB on the LD50 of Y. enterocolitica in C57BL/6 and BALB/c mice might be due to an immunomodulating effect of DFOB.

Animals↗
PubMed1994

Salmonella enteritidis orchitis in a 10-week-old boy.

Extraintestinal manifestations of salmonellosis in paediatric patients are found predominantly in infants less than three months of age. Genital involvement is a rare complication. We present a short review of the literature and describe the case of a 10-week-old boy suffering from severe diarrhoea, who presented with a swelling of the right testicle after six days of illness. He underwent surgery on suspicion of testicular torsion, whereby orchitis was diagnosed. Salmonella enteritidis was cultured from the intraoperative swab. All cultures from blood, CSF and urine remained sterile. We conclude that orchitis must be taken into consideration as an extraintestinal complication of enteric salmonellosis and as a differential diagnosis of testicular torsion. In addition, we wish to emphasize that any infant less than three months of age with suspected or proven salmonellosis, should receive early antibiotic treatment.

Anti-Bacterial Agents↗
PubMed1993

Role of plasmid-encoded antigens of Yersinia enterocolitica in humoral immunity against secondary Y. enterocolitica infection in mice.

In the present study the role of Yersinia enterocolitica antigens in humoral immunity against secondary Y. enterocolitica infection has been investigated. For this purpose, BALB/c mice, 4 weeks after immunization by primary infection with a sublethal dose of various Y. enterocolitica strains and mutant strains, were challenged with a lethal dose of highly virulent Y. enterocolitica strains of serotype O:8. As evident from the survival rate and protection against bacterial growth in the spleens of mice, only immunization with wild-type or attenuated strains harbouring an intact virulence plasmid mediated protection against a lethal challenge. Protection by immunization with plasmid-harbouring strains correlated with persistence of the bacteria in spleens for at least 7 days after immunization and high serum titres of Yersinia-specific antibodies directed against both chromosomal and plasmid-encoded determinants. Furthermore, the adoptive transfer of the purified IgG fraction of a rabbit serum specific for the adhesin YadA encoded by virulence plasmid pO8 from Y. enterocolitica O:8 mediated protection against a lethal challenge with the serotype O:8 strain harbouring the virulence plasmid pO8 but did not mediate protection when this strain harboured the virulence plasmid pO9 from serotype O:9. In summary, the results demonstrate that in our experimental mouse infection model: (i) the presence of the intact virulence plasmid in an immunizing Y. enterocolitica strain is essential for induction of protection against a lethal challenge with highly virulent Y. enterocolitica and (ii) that antibodies against plasmid-encoded determinants of Y. enterocolitica, especially YadA, are of major importance for achievement of protective immunity in mice.

Animals↗
PubMed1993

Pseudomonas aeruginosa in a neonatal intensive care unit: reservoirs and ecology of the nosocomial pathogen.

Pseudomonas aeruginosa is one of the leading nosocomial pathogens. In hospitals, organisms are commonly recovered from moist environments. To determine the reservoir and population dynamics of particular strains, highly discriminative typing methods are required. Hybridization of enzymatically restricted P. aeruginosa DNA with two gene probes led to the identification of infecting and colonizing strains prevalent over a 5-month period in a neonatal intensive care unit. Four genotypically distinct strains were repetitively isolated from tap water from several faucets on the ward. P. aeruginosa isolates recovered from tap water on adjacent wards supplied by the same water system had different genotypes, while samples taken from the mains were negative for the organism. Serotyping of O antigens showed variable reproducibility and could not elucidate the strain-specific reservoirs. It is concluded that organisms are transmitted horizontally between faucets and prevail in reservoirs for prolonged periods.

Blotting, Southern↗
PubMed1993

Virulence of Yersinia enterocolitica is closely associated with siderophore production, expression of an iron-repressible outer membrane polypeptide of 65,000 Da and pesticin sensitivity.

Iron-repressible outer membrane proteins (Irp) and siderophore production of Yersinia enterocolitica, serotype 08, were subjected to analysis. Here four Irps of apparent molecular weights of 62,000, 65,000, 74,000 and 75,000 could be identified which were expressed constitutively by a fur mutant. Production of a novel catechol-containing siderophore (denoted yersiniabactin) was detected by siderophore-indicator agar (chrome azurol S) and feeding experiments. Growth support by yersiniabactin under iron-restricted conditions was TonB- and Irp65-dependent and correlated with pesticin-sensitivity of Yersinia enterocolitica and Escherichia coli O. From these results we conclude that Irp65 of Y. enterocolitica functions as yersiniabactin receptor (FyuA) and as pesticin receptor. By immunoblotting using rabbit antibodies against Irp65 and chrome azurol S-agar, we were able to demonstrate that all tested mouse-lethal Y. enterocolitica and Yersinia pseudotuberculosis strains of different serotypes express siderophores and Irp65. Moreover, the anti-Irp65 rabbit serum did not cross-react with the known iron-repressible high-molecular-weight proteins (HMWPs). Evidently, the mouse lethality trait in enteropathogenic Yersinia spp. is closely associated with a novel iron-uptake system, comprising the production of a siderophore and a siderophore receptor of apparent molecular mass 65,000 Da.

Animals↗
PubMed1988

Therapeutic activity of teicoplanin on experimental listeriosis compared with that of vancomycin and ampicillin.

Several strains of Listeria monocytogenes and other Listeria spp. are without exception susceptible to teicoplanin (MIC 0.25 mg/l). Vancomycin as well as ampicillin are likewise active. A bactericidal effect of teicoplanin was only achieved at rather high concentrations and after incubation of several hours. There is no synergistic effect between teicoplanin and gentamicin. The therapeutic activity of teicoplanin as well as vancomycin in mice infected with L. monocytogenes is low. The efficacy of ampicillin could not be achieved. Treatment of chronically infected athymic, nude mice with teicoplanin is ineffective. Consequently, teicoplanin is not able to replace ampicillin in the therapy of listeriosis.

Ampicillin↗
PubMed1983

Peritrophic membranes and protease activity in the midgut of the malaria mosquito, Anopheles stephensi (Liston) (Insecta: Diptera) under normal and experimental conditions.

Formation and solubility of the peritrophic membranes (pm) in the midgut (stomach) of female Anopheles stephensi depended on salt concentration in the gut lumen. High calcium drastically reduced the solubility of the pm in vitro. Thin-layer chromatography revealed the presence of N-acetylgalactosamine and galactose in the pm. In contrast to Aedes aegypti no N-acetylglucosamine was present indicating significant differences between Anopheles and Aedes mosquitoes with respect to pm formation and composition. Experimental distension of the stomach epithelium did not trigger secretion of proteases, but membrane-bound granules were released from the stomach cells, and pm were formed. When females were fed blood 18 hr after an enema with salt solution, when practically no granules were present in the gut cells, protease activity was increased, and blood was digested normally, but no pm were formed. A functional correlation of the membrane-bound granules and pm formation is postulated. alpha-Amanitin prevented normal digestion, protease activity was only insignificantly increased, and no pm formed after blood intake.

Animals↗
PubMed1981

[Accidents related to physical education in school: epidemiologic and preventive approach].

Generally speaking, this category of accidents seems to cause mostly relatively mild injuries. It could explain, at least in part, why there are so few papers on this topic in the medical literature except for clinical reports usually based on hospitalized cases. The main results of a study of the 9261 physical education accidents registered within five years in primary and secondary schools in Basle and Geneva are used to illustrate their epidemiological characteristics, as well as the localization and the severity of the injuries. The sources of data are the files of the accident insurance companies. Initial operational definitions, data sources, measurement of exposure to risk and the (largely criticized) notion of individual accident proneness are constraints and conditions of a pertinent epidemiological approach which have to be carefully taken into consideration. This approach should be combined with the clinical and the ergonomical approaches in order to get the best possible pictures of the causes, mechanisms and consequences not only of accidents in general but especially of those occurring in physical activities in childhood and adolescence. Some considerations on prevention are briefly outlined here. They intend to take into account the risk factors related to the tasks, the circumstances and especially to the student himself taken as an individual involved in a growth and development dynamics.

Adolescent↗
PubMedDate not supplied

RSV-prevention in children guided by a web-based early warning system.

BACKGROUND: Passive immunization with palivizumab is expensive and requires considerable logistic effort. So far 5 monthly injections from November to March are recommended. The RSV season onset and its duration, however, shows considerable variation. In many countries on the northern hemisphere a dual rhythm is described. METHOD: A web-based early warning system within the research network PID-ARI.net is in place since 2002. The surveillance data are published online weekly via www.pid-ari.net. This enables physicians to carry out interventions, like passive immunization for RSV, synchronously with the epidemiology of a given pathogen instead of a rigid schedule. The surveillance of PID-ARI.net is based on a 19 valent multiplex RT-PCR on naso-pharyngeal aspirates. The samples are provided by hospitals and offices in Freiburg, Mainz and Schleswig-Holstein (north, middle, south of Germany). Children with lower airway infections are prospectively enrolled. RESULTS: In the time period from July 1999 to June 2003 with 20 months of recommended palivizumab application, 5 months (25 %) would have been not on target. In two seasons the start of the vaccine campaign would have been too early (waste of two months). In one season the application would have started one month too late and in two seasons the vaccine campaign would have been stopped two months too early leaving the vaccinees on risk for acquiring RSV. CONCLUSIONS: The web-based early warning system of PID-ARI.net is the first, pathogen-specific, comprehensive and fast surveillance-system for airway pathogens in Europe. It facilitates the epidemic-synchronous use of the passive immunization with palivizumab and by this increases its efficiency and should safe costs.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Bacteremic episodes in pediatric oncologic patients, especially caused by the Streptococcus viridans group].

BACKGROUND: The management of infectious complications plays a major role in the care for pediatric cancer patients. The majority of infections in the neutropenic patient present as fever of unknown origin without recovering a pathogen from the blood stream. The careful evaluation of bacteremic episodes is essential, since knowledge of the bacterial spectrum expected is crucial for the successful anti-infective treatment. PATIENTS AND METHODS: From 1985 to 1995 all bacteremic episodes in pediatric oncology patients at the University Children's Hospital Freiburg were retrospectively analyzed with respect to the pathogens encountered, the antibiotic susceptibility profile and the underlying conditions. RESULTS: Overall, 113 bacteremic episodes were encountered in pediatric oncology patients, 68 of them in patients with hematological malignancies, and 45 in patients with solid tumors. In both patient groups, gram-positive bacteria were predominant with 72% and 58%, respectively. In patients with hematological malignancies, viridans streptococci were the most frequently isolated pathogens (35%) with a relevant morbidity (29% of patients developed a severe sepsis syndrome and/or ARDS), but were found only in 9% of patients with solid tumors. In 28% of patients with leukemia or lymphoma, gram-negative rods were cultured, in 6% Pseudomonas spec., in 4% Acinetobacter spec., and in 18% enterobacteria. In patients with solid tumors, in 38% gram-negative rods were isolated, 7% Pseudomonas spec., 16% Acinetobacter spec., 16% enterobacteria. In 3 patients, fungemia was observed. The antibiotic susceptibility profile was quite favorable in both, gram-positive and -negative bacteria: none of the gram-positive isolates was resistant to vancomycin, none of the Staphylococcus aureus isolates was resistant to oxacillin. All gram-negative bacteria were fully susceptible to ceftazidime, imipenem and ciprofloxacin. CONCLUSION: Gram-positive bacteria account for 2/3 of all bacteremic episodes in pediatric oncology patients. Streptococcus viridans was the most important pathogen in hematological malignancies accounting for a significant, pathogen-specific morbidity.

Adolescent↗
PubMedDate not supplied

[Miliary tuberculosis and adult respiratory distress syndrome in an infant].

We report on a 7 months old infant, who was admitted to our hospital with the tentative diagnosis of interstitial pneumonia. The infant was treated with erythromycin because of a positive mycoplasma antigen test in the nasopharyngeal mucus and the radiological findings. A tension pneumothorax led to rapid respiratory deterioration and a severe ARDS developed. A sustained respiratory stabilization could not be achieved. The diagnosis miliary tuberculosis was detected on autopsy. A parenchymal focus was found subpleurally in the left lung with a massive hematogenous spread and a tuberculous meningitis. The source of infection could not be identified in the family or in persons known to have had contact to the infant. The tuberculin skin test (PPD) was negative. Clinical, radiological and pathological findings are demonstrated.

Diagnosis, Differential↗
PubMedDate not supplied

[Kinetics of myelopoietic regeneration and mobilization of CD34-positive cells within the scope of the NB90 Neuroblastoma Therapy Study].

Hematological and clinical data of 14 children with neuroblastoma treated according to the German neuroblastoma therapy study NB 90 were analyzed. Therapy included 4 or 8 intensive therapy elements N1 (Etoposide 125 mg/m2 day 1-4, Vindesine 3 mg/m2 day 1, Cisplatin 40 mg/m2 day 1-4) and N2 (Vincristine 1.5 mg/m2 day 1 + 8, Dacarbazine 200 mg/m2 day 1-5, Ifosfamide 1500 mg/ m2 day 1-5, Doxorubicin 30 mg/m2 day 6 + 7) in alternating order. The hematological recovery was studied after 86 therapy elements N1/N2. G-CSF had been given in 23 therapy courses, while no cytokine was administered in 63 therapy courses. Mobilization of CD34+ cells was studied in 13 therapy courses with G-CSF. Severe myelosuppression with an absolute neutrophil count < 500/microL was noted 2-4 weeks after each therapy element. The use of G-CSF did not prevent, but shortened neutropenia. There was no difference in the number of infections nor time delay of therapy between the courses with or without G-CSF. In 11 therapy courses G-CSF was started on the day following the last chemotherapy dose (N1: day 5; N2: day 9). In 12 therapy courses G-CSF was given delayed, starting day 12 after the initiation of therapy. Kinetics of granulocyte recovery was similar in the early or delayed application of G-CSF. Neutrophil recovery after the therapy element N1 was earlier and faster compared to that of therapy element N2. The more rapid rise of the neutrophils after the N1 element was accompanied by an effective mobilization of CD34+ cells. Taking into account the limitations of this retrospective study, the data may help to optimize the application of G-CSF in a very intensive therapy study like NB90.

Adolescent↗