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O Werner

Publications and source records attributed to O Werner.

At least 19 recordsLinked to original sources
PubMed2006

A virological survey in migrating waders and other waterfowl in one of the most important resting sites of Germany.

Wild birds are considered a potential reservoir or a carrier of viral diseases and may therefore play a role in the epidemiology of economically important or zoonotic diseases. In 2001 and 2002, a survey with special emphasis on virus isolation in migrating waders and some other birds were conducted. In one of the most important inland resting sites for migratory waterfowl, tracheal and cloacal swabs were collected from 465 waders representing 19 different species, and 165 other birds that were not captured on purpose. A total of 42 avian viruses were isolated, 34 of these were identified as paramyxoviruses (PMVs). The majority of isolates came from waders and wild ducks, and were characterized as PMV-1. In contrast, PMV-4 was found in wild ducks only, PMV-6 was mainly detected in wader species. Four avian influenza viruses (AIVs), belonging to H4 and H3 haemagglutinin subtype, were isolated from wild duck species. Furthermore, four reo-like viruses were isolated from one particular wader species for the first time. The majority of virus positive birds were <1 year old and did not show any clinical symptoms. There was no evidence for the presence of West Nile virus in these birds. These results confirm that the restricted resting sites in Western Europe must be considered as important locations for the intra- and interspecies transmission of avian viruses.

Animal Migration↗
PubMed2006

Establishment of a competitive ELISA (cELISA) system for the detection of influenza A virus nucleoprotein antibodies and its application to field sera from different species.

A recombinant baculovirus (RBV) encoding the nucleoprotein (NP) of avian influenza virus (AIV) was generated and the appropriate protein was expressed in Sf9 cells. Purified recombinant NP and the NP-specific monoclonal antibody HB65 were used to establish a competitive ELISA (cELISA) system for the detection of NP-specific antibodies in sera of ducks, geese and wild birds. Tests to evaluate this method were carried out using sera of ducks experimentally infected with AIV, pre-immune duck and chicken sera, and poultry field sera, which tested negative in the haemagglutination inhibition (HI) assay, and field sera of several poultry species experimentally infected with other viruses. The evaluation of the test demonstrated a high sensitivity and specificity of this method. Tests carried out using field sera of duck and goose flocks revealed widely corresponding results obtained by HI assay and cELISA indicating that this test is applicable for flock diagnosis. Differing results were obtained for individual samples. It can be assumed that for the most part this was because of a better recognition of the conserved NP antigen by serum antibodies, although some results remained unclear.

Animals↗
PubMed2006

Neurotropism of highly pathogenic avian influenza virus A/chicken/Indonesia/2003 (H5N1) in experimentally infected pigeons (Columbia livia f. domestica).

This investigation assessed the susceptibility of experimentally infected pigeons to the highly pathogenic avian influenza virus (HPAIV) H5N1 that caused recent outbreaks of avian influenza in birds and humans in several countries of Asia. For this purpose 14 pigeons were infected ocularly and nasally with 10(8) EID50 and clinical signs were recorded and compared with five chickens infected simultaneously as positive controls. The chickens demonstrated anorexia, depression, and 100% mortality within 2 days postinoculation. Three of the pigeons died after a history of depression and severe neurological signs consisting of paresis to paralysis, mild enteric hemorrhage, resulting in a mortality of 21%. Gross lesions in these pigeons were mild and inconsistent. Occasionally subcutaneous hyperemia and hemorrhage and cerebral malacia were observed. Microscopic lesions and detection of viral antigen were confined to the central nervous system of these pigeons. In the cerebrum and to a minor extent in the brain stem a lymphohistiocytic meningoencephalitis with disseminated neuronal and glial cell necrosis, perivascular cuffing, glial nodules, and in one bird focally extensive liquefactive necrosis could be observed. The remaining nine pigeons showed neither clinical signs nor gross or histological lesions associated with avian influenza, although seroconversion against H5 indicated that they had been infected. These results confirm that pigeons are susceptible to HPAIV A/chicken/Indonesia/2003 (H5N1) and that the disease is associated with the neurotropism of this virus. Although sentinel chickens and most pigeons did not develop disease, further experiments have to elucidate whether or not Columbiformes are involved in transmission and spread of highly pathogenic avian influenza.

Animals↗
PubMed2004

[Zoonoses in working- and wild animals and their significance in Germany. An overview].

The control of infectious diseases transmitted from animals to humans (zoonoses) was recently put on a new basis in the European Union when a new Zoonoses Directive entered into force. Brucellosis, campylobacteriosis, echinococcosis, listeriosis, salmonellosis, trichinosis, and the respective causative agents, tuberculosis due to Mycobacterium bovis, and verotoxigenic Escherichia coli must be included in monitoring. Additional zoonoses and zoonotic agents are to be monitored according to the epidemiological situation. Against this background, the current knowledge on important zoonoses transmitted from livestock and some wildlife animals to humans as well as the epidemiological situation in Germany with regard to these diseases is summarized.

Animals↗
PubMed2003

A lung recruitment maneuver immediately before rescue surfactant therapy does not affect the lung mechanical response in immature lambs with respiratory distress syndrome.

BACKGROUND: In animals with acquired surfactant-deficiency, a recruitment maneuver by increased tidal volumes enhances the effect of exogenous surfactant. In contrast, in the preterm lamb model, hyperinflation early after birth impairs the effect of surfactant prophylaxis. Here we examined whether a lung recruitment maneuver just before surfactant would affect the response to rescue treatment in immature lambs with established respiratory distress syndrome (RDS). METHODS: Five pairs of preterm twin lambs with gestational age 127 days were delivered by cesarean section and supported by pressure-limited mechanical ventilation for 4 h. At 30 min of age, when all the lambs were in severe respiratory failure, they were treated with porcine surfactant, 200 mg x kg-1. One lamb in each pair was subjected to a lung recruitment maneuver consisting of five sustained inflations of 20 ml x kg-1 just before surfactant instillation. RESULTS: At 10 min after surfactant treatment, all the lambs showed a large improvement in oxygenation and an increase in inspiratory capacity and static compliance. Except for a transiently better oxygenation after surfactant therapy in the recruitment group (P < 0.05), there was no significant between-group differences in gas exchange or lung mechanics at any time point during the study. There was no difference in post mortem intrapulmonary air volume or alveolar expansion in histologic lung sections between groups. CONCLUSION: This small study does not show any positive or negative effect of a lung recruitment maneuver on the response to rescue surfactant therapy in immature animals with RDS.

Animals↗
PubMed2003

Isolation and characterization of a low-pathogenicity H7N7 influenza virus from a turkey in a small mixed free-range poultry flock in Germany.

A hemagglutinating virus was isolated from a dead turkey in a small mixed free-range flock in Southern Germany. It was identified as influenza virus type A of subtype H7N7. The pathogenicity was low. An intravenous pathogenicity index of 0.03 was recorded, and the nucleotide sequencing revealed the amino acid sequence NVPEIPKGR*GLFG at the cleavage site of the hemagglutinin. Antibodies as well as virus were detected in the affected flock. Further virus spreading to other flocks was prevented by stamping out policy. Serological monitoring of contact flocks revealed one small backyard flock of 18 hens, which was positive. This flock was also destroyed. The origin of the virus could not be identified.

Amino Acid Sequence↗
PubMed2003

Detection of H7 avian influenza virus directly from poultry specimens.

Using clinical materials from experimentally infected poultry, we established an effective method for the preparation of viral RNA directly from tissue samples and eggs. Furthermore, our type A-specific matrix reverse transcription-polymerase chain reaction (RT-PCR) test was improved, and an H7 subtype-specific nested RT-PCR, which includes the hemagglutinin cleavage site, was designed. Both RT-PCR systems proved to be as sensitive as virus isolation. In addition, the labeled H7 HA-nested PCR primers were suitable for sequencing of the PCR products. The RT-PCR amplification of viral RNA and sequencing of the PCR product allows for the sensitive and rapid differentiation between low-pathogenic and highly pathogenic avian influenza viruses.

Animals↗
PubMed2002

Airway closure in anesthetized infants and children: influence of inspiratory pressures and volumes.

BACKGROUND: Cyclic opening and closing of lung units during tidal breathing may be an important cause of iatrogenic lung injury. We hypothesized that airway closure is uncommon in children with healthy lungs when inspiratory pressures are kept low, but paradoxically may occur when inspiratory pressures are increased. METHODS: Elastic equilibrium volume (EEV) and closing capacity (CC) were measured with a tracer gas (SF(6)) technique in 11 anesthetized, muscle-relaxed, endotracheally intubated and artificially ventilated healthy children, aged 0.6-13 years. Airway closing was studied in a randomized order at two inflation pressures, +20 or +30 cmH(2)O, and CC and CC/EEV were calculated from the plots obtained when the lungs were exsufflated to -20 cmH(2)O. (CC/EEV >1 indicates that airway closure might occur during tidal breathing). Furthermore, a measure of uneven ventilation, multiple breath alveolar mixing efficiency (MBAME), was obtained. RESULTS: Airway closure within the tidal volume (CC/EEV >1) was observed in four and eight children (not significant, NS) after 20 and 30 cmH(2)O inflation, respectively. However, CC(30)/EEV was >CC(20)/EEV in all children (P< or = 0.001). The MBAME was 75+/-7% (normal) and did not correlate with CC/EEV. CONCLUSION: Airway closure within tidal volumes may occur in artificially ventilated healthy children during ventilation with low inspiratory pressure. However, the risk of airway closure and thus opening within the tidal volume increases when the inspiratory pressures are increased.

Adolescent↗
PubMed2002

Genetic variability in a narrow endemic snapdragon (Antirrhinum subbaeticum, Scrophulariaceae) using RAPD markers.

Antirrhinum subbaeticum is an endangered species inhabiting fragmented limestone cliffs. In the last 3 years, a drastic population decline has been observed in three of four known populations and the estimated number of surviving individuals is now close to 400. A RAPD study was conducted to evaluate the levels of genetic variation present in this species to improve conservation guidelines. Thirty-nine polymorphic products identified 66.1% of the samples by unique RAPD multilocus profiles. A cluster analysis grouped the samples into two broad groups corresponding to northern or southern provenances. AMOVA analysis showed that only 17.7% of the genetic diversity was partitioned within populations. These results are in contrast to data available for other Antirrhinum species. This genetic structure could be explained by the predominant selfing behaviour exhibited by A. subbaeticum as opposed to the allogamy of other congeners. Genetic diversity within populations does not seem to be strongly related to population size and historical factors could be responsible for the very low levels of genetic diversity found in one population. Given the low genetic diversity within populations, it is suggested that an extensive sampling of individuals be made for recovering appropriate levels of the gene pool for ex situ preservation. However, translocation of individuals to the genetically weakened Bogarra population from other sources is not recommended.

Antirrhinum↗
PubMed2002

Avian paramyxovirus serotype 1 isolates from the spinal cord of parrots display a very low virulence.

The spinal cord of 32 psittacines suffering from proventricular dilatation disease (PDD) was investigated. In six cases, a virus was isolated which upon electron microscopic examination revealed morphological details typical of members of the Paramyxoviridae. All isolates were subsequently characterized as avian paramyxovirus serotype 1 (APMV-1) by type-specific polyclonal antisera. According to their reactivity with APMV-1 specific monoclonal antibodies, the six isolates shared epitopes within the haemagglutinin-neuraminidase spike protein, distinct from pigeon-type paramyxoviruses and the LaSota vaccine strain. This grouping was further corroborated by properties of the haemagglutinin: all isolates showed a very thermosensitive haemagglutination activity and were rapid eluters. Virulence of the APMV-1 isolates in 1-day-old specific pathogen free (spf) chicken was very low, with intracerebral pathogenicity indices between 0 and 0.1. In embryonated spf chicken eggs, psittacine isolates replicated to high titres (10(8.6)-10(10.7) EID50/ml). However, they exhibited a reduced lethality over an observation time of 7 days (10(6.1)-10(8.3) ELD50/ml). In a haemagglutination inhibition test with parrot sera from birds with no history of APMV-1 vaccination, sera reacted preferentially with two isolates compared with APMV-1 vaccine strains LaSota and B1. The other four isolates exhibited a differentiated reaction pattern with the parrot sera, indicating an antigenic inhomogeneity. This is the first report of isolating very low virulent APMV-1 from neuronal tissue of parrots and implications for a possible role in slow progressing disease will be discussed.

Animals↗
PubMed2001

Reduced postnatal cerebral glucose metabolism measured by PET after asphyxia in near term fetal lambs.

The effects of fetal asphyxia on cerebral function and development, involve the transition from fetal to neonatal life. Changes in cerebral glucose metabolism may be an early postnatal indicator of fetal asphyxia. The objective is to develop an experimental lamb model involving the transition from fetal to neonatal life and to examine the effect of fetal asphyxia with cerebral hypoxic ischemia on early postnatal cerebral glucose metabolism. Fetal asphyxia was induced by total umbilical cord occlusion in eight near-term fetal lambs (134-138 days) with the ewe under isoflurane-opiate anesthesia. The mean occlusion time until cardiac arrest was 14.5 (4.2) min (SD). Lambs were immediately delivered and standardized resuscitation was instituted after 2 min asystole. At 4 hr postnatal age, [18-F]Fluoro-2-deoxy-glucose (18-FDG) was injected intravenously in eight asphyxiated lambs and in eight controls. Cerebral glucose metabolism was examined by positron emission tomography (PET). As a result the mean arterial blood pressure, acid-base values, blood glucose and serum lactate at 4 hr postnatal age did not differ significantly between lambs subjected to umbilical cord occlusion and controls. EEG was abnormal in all lambs subjected to cord occlusion and normal in the controls at 4 hr postnatal age. Global cerebral metabolic rate (CMRgl) as determined by PET was significantly lower in lambs subjected to cord occlusion mean/median (SD) 22.2/19.6 (8.4) micromol/min/100 g) than in controls mean/median (SD) 37.8/35.9 (6.1); P < 0.01). Global CMRgl is significantly reduced in newborn lambs 4 hr after fetal asphyxia induced by umbilical cord occlusion. A reduction in CMRgl is an early indicator of global hypoxic cerebral ischemia.

Acidosis↗
PubMed2001

Protection of chickens from lethal avian influenza A virus infection by live-virus vaccination with infectious laryngotracheitis virus recombinants expressing the hemagglutinin (H5) gene.

The H5 hemagglutinin (HA) gene of a highly pathogenic avian influenza virus (AIV) isolate (A/chicken/Italy/8/98) was cloned and sequenced, and inserted at the non-essential UL50 (dUTPase) gene locus of a virulent strain of infectious laryngotracheitis virus (ILTV). Northern and Western blot analyses of the obtained ILTV recombinants demonstrated stable expression of the HA gene under control of the human cytomegalovirus immediate-early gene promoter. In vitro replication of the HA-expressing ILTV mutants was not affected, and infection of chickens revealed a reduced but still considerable virulence, similar to that of a UL50 gene deletion mutant without foreign gene insertion. The immunized animals produced specific antibodies against ILTV and AIV HA, and were protected against challenge infections with either virulent ILTV, or two different highly pathogenic AIV strains (A/chicken/Italy/8/98, A/chicken/Scotland/59). After challenge, no ILTV could be reisolated from protected animals, and shedding of AIV was considerably reduced. Thus, although attenuation remains to be improved, genetically engineered ILTV live-virus vaccines might be used as vectors to protect chickens also against other pathogens.

Animals↗
PubMed2001

The pressure at the lower inflexion point has no relation to airway collapse in surfactant-treated premature lambs.

BACKGROUND: The lower inflexion point (LIP) on the inspiratory part of the pressure-volume (PV) loop has been suggested to be related to the pressure at which air spaces collapse. Our hypothesis is that airway collapse might instead be assessed from the upper inflexion point on the expiratory part of the PV-loop (UIPexp), where lung volume starts to decrease significantly. We therefore examined whether there was a relation between LIP and UIPexp in premature surfactant-treated lambs. METHODS: Ten lambs, at 119-141 days of gestational age, were delivered by cesarean section and given 200 mg/kg modified natural porcine surfactant before the first breath. The lambs were then connected to a ventilator and PV-loops using airway pressures of 0-35-0 (ZEEP-loop) and 5-35-5 cmH2O (PEEP-loop) were obtained after lung recruitment at 15, 60 and 120 min after birth. From the loops, LIP, UIPexp, upper inflexion point of the inspiratory part of the loop (UIP insp), inspiratory capacity (IC) as well as inspiratory and expiratory maximal compliance of the respiratory system (Crs(insp) and Crs(exp)) were calculated. RESULTS: The ZEEP-loop showed a substantial hysteresis with a distinct LIP at 19+/-2 cmH2O (mean+/-SD), which was different (P<0.001) from UIPexp (9+/-2 cmH2O). The pressures at LIP and UIPexp were unrelated (r2=0.06). UIPinsp was located at 28+/-2 cmH2O. Crs(insp) was 2.1+/-0.6 ml x cmH2O(-1) x kg(-1), which was lower (P<0.001) than Crs(exp) (2.8+/-0.6 ml x cmH2O(-1) x kg(-1)). IC was 26+/-6 ml/kg. The PEEP-loop had a minimal hysteresis with an expiratory part coinciding with that of the ZEEP-loop. CONCLUSION: In surfactant-treated premature lambs the pressures at LIP and UIPexp are not related, showing that LIP does not indicate the pressure at which airways collapse.

Anesthesia↗
PubMed2001

Lung recruitment at birth does not improve lung function in immature lambs receiving surfactant.

BACKGROUND: In mature animals with surfactant deficiency induced by lung lavage, the therapeutic effect of exogenous surfactant is enhanced by a lung recruitment maneuver. We then tested whether a lung recruitment maneuver at birth immediately before surfactant treatment would improve lung function also in preterm lambs with surfactant deficiency due to immaturity. METHODS: Ten newborn lambs with a gestational age of 127 days were randomized to receive surfactant either before the first breath or immediately after a lung recruitment maneuver consisting of five sustained inflations of 8, 16 or 32 ml/kg. Functional residual capacity was measured by sulfur hexafluoride washout, and inspiratory capacity as well as maximal compliance were obtained from a static expiratory pressure-volume curve after the lungs had been inflated to 35 cm H2O. In addition, blood gases were obtained. Measurements were made at 15, 45, 175, 135, 170 and 230 min after birth. Post mortem histological examinations of the lungs were performed in a blinded fashion. RESULTS: The lung recruitment maneuvers did not improve oxygenation. Inspiratory capacity, static compliance and functional residual capacity at 4 h, as well as post mortem intrapulmonary air volume, had an inverse relation to the size of inflations given at birth. There was also a negative correlation between size of inflations at birth and response to surfactant therapy, as assessed by lung microscopy. CONCLUSION: Lung recruitment at birth does not improve the response to surfactant in immature lambs, but may instead have an adverse effect on lung function and morphology.

Animals↗
PubMed2000

Type- and subtype-specific RT-PCR assays for avian influenza A viruses (AIV).

Reverse transcriptase (RT) PCR assays have been developed to improve the diagnosis of avian influenza A. RT-PCR using primers complementary to a conserved region of the matrix protein was assessed as being suitable for the detection of influenza A virus RNA from poultry as well as from pigs, horses and humans, regardless of the haemagglutinin (HA) and neuraminidase (NA) subtype. Therefore, this RT-PCR is a valuable tool to confirm the initial diagnosis of any influenza A infection. As a second approach, experiments were performed to identify the HA gene encoding the post-translational cleavage site of potentially highly pathogenic AIV isolates by RT-PCR. The principal aim was to design one universal primer pair for each virus subtype, H5 and H7, respectively, which allows the detection of all strain variants using only one consistent method. To realize this objective, it was necessary to develop 'wobble' primers. AIV RNAs from seven H5 and 11 H7 subtype viruses included in the investigations were specifically recognized by RT-PCR using these primers. This method therefore provides a rapid, subtype-specific diagnosis and subsequent sequencing of H5 and H7 avian influenza viruses.

Animals↗
PubMed2000

The Reflector: a new method for saving anaesthetic vapours.

Anaesthesia systems that minimize the use of volatile anaesthetics to reduce cost and pollution are of interest. Closed circuit anaesthesia is the ideal solution, but requires continuous adjustment of fresh gas flow and composition and thus is demanding in routine practice. We describe an alternative system, the Reflector system, which is open in regard to oxygen, nitrogen and N2O, and semiclosed in regard to volatile anaesthetics. The Reflector system is a circle system with a carbon dioxide absorber and an automatic vapour delivery device placed in the inspiratory limb of the circle. A zeolite filter, the Reflector, is placed between the ventilator and the circle. The Reflector functions as a molecular sieve, preventing the volatile anaesthetic from leaving the circle. Isoflurane consumption using the Reflector system in bench tests and an animal study was compared with that of an open system. In bench tests consumption was reduced by 79% and 82%, at a respiratory frequency of 10 and 20 min-1, respectively. The corresponding mean figures from the animal experiment were 65% and 77%.

Anesthesia↗