Detection and identification of food-borne pathogens of the genera Campylobacter, Arcobacter and Helicobacter by multiplex PCR in poultry and poultry products

The objective of this study was to develop a multiplex polymerase chain reaction (PCR) to detect and differentiate food-borne pathogens of the three genera Campylobacter, Arcobacter and Helicobacter in a single step procedure. One common reverse primer and three genus-specific forward primers were designed by hybridizing to the 16S rRNA of selected reference strains. Besides the species with significance as food-borne pathogens isolated from poultry meat--Campylobacter jejuni, Campylobacter coli, Arcobacter butzleri and Helicobacter pullorum--several other members of these genera were tested to determine the specificity of the designed multiplex PCR. In total, 20 ATCC and NCTC reference strains of Campyobacter, Arcobacter and Helicobacter were used to evaluate the PCR. Specific amplificates were obtained from all thermophilic species of Campylobacter as well as from species of Arcobacter and Helicobacter. No amplification product was obtained from the non-thermophilic Campylobacter, C. hyointestinalis and C. fetus. Furthermore, a total of 43 field strains of the three genera isolated from poultry, pigs, cattle and humans were investigated using this PCR. To confirm the classification of 10 H. pullorum strains the 16S rRNAs were sequenced. The developed PCR is a helpful diagnostic tool to detect and differentiate Campylobacter, Arcobacter and Helicobacter isolated from poultry and poultry products.

YAC/BAC contig spanning the MHC class III region of cattle

A contig of the class III region of the bovine major histocompatibility complex (MHC) was established from bacterial and yeast artificial chromosomes using PCR and BAC-end sequencing. The marker content of individual clones was determined by gene and BAC-end specific PCR, and the location of genes and BAC-ends was confirmed analyzing somatic hybrid cells. A comparative analysis indicated that the content and order of MHC class III genes is strongly conserved between cattle and other mammalian species. Fluorescence in situ hybridization localized the bovine class III region to BTA23q21-->q22. The results show that the collection of sequenced BAC-ends is a powerful resource for generating high-resolution comparative chromosome maps.

Broad dissemination of Histomonas meleagridis determined by the detection of nucleic acid in different organs after experimental infection of turkeys and specified pathogen-free chickens using a mono-eukaryotic culture of the parasite

Histomonas meleagridis, a flagellated protozoan parasite, is the causative agent of histomonosis (syn. histomoniasis, blackhead) in turkeys and chickens. The organs primarily affected by the parasite are the caeca and the liver. Until now, only few reports exist in which the parasite has been diagnosed in tissues other than those mentioned above. Hence, the aim of this study was to perform a systematic investigation of various organs of turkeys and specified pathogen-free chickens following an experimental infection with a mono-eukaryotic culture of Histomonas meleagridis in order to determine the dissemination of the flagellate in infected birds. Molecular methods like PCR and in situ hybridization were used for this purpose. For the first time, the DNA of the parasite could be detected in 13 different organs of infected turkeys by PCR including the proventriculus, duodenum, jejunum, caeca, pancreas, bursa of Fabricius, liver, kidney, spleen, heart, lung, thymus and the brain. Most of these findings were further confirmed by in situ hybridization. In contrast to the turkeys that all died shortly after the infection, all of the chickens survived without displaying any clinical symptoms. Even at necropsy, only mild pathological changes were observed in the caeca. Nevertheless, the parasite could also be detected in various organs of these birds, namely the caeca, bursa of Fabricius, kidney, heart and the brain.

PCR for the identification and differentiation of Histomonas meleagridis, Tetratrichomonas gallinarum and Blastocystis spp

In the present investigation PCR assays were developed for the rapid detection and differentiation of two poultry flagellates: Histomonas meleagridis and Tetratrichomonas gallinarum as well as the protozoan microorganism: Blastocystis spp. The nucleotide sequences of the small subunit ribosomal RNAs were used for primer construction obtaining fragments which vary in size for each microorganism. The established PCRs were able to detect DNA obtained from one microorganism of T. gallinarum and Blastocystis spp. propagated in vitro, proving the high analytical sensitivity of the method. DNA isolated from 10 protozoa was sufficient to detect H. meleagridis. To assess specificity, each PCR assay was performed with DNA from either H. meleagridis and/or T. gallinarum and/or Blastocystis spp. as well as with DNA from several other protozoan parasites (Eimeria tenella, Toxoplasma gondii, Cryptosporidia spp., Trichomonas gallinae, Entamoeba invadens, Entamoeba ranarum), fungi (Aspergillus fumigatus, Candida albicans), bacteria (Staphylococcae, Streptococcae, E. coli, Clostridium perfringens, Camplyobacter jejuni, Proteus) and viruses (fowl adenovirus serotype 4, avian reovirus) as well as livers and caecal samples from turkeys and specified pathogen free (spf) chickens. No cross-reactions with any of these samples were observed with the primer sets for the detection of H. meleagridis and Blastocystis spp. The primers designed for the identification of T. gallinarum yielded a PCR product with DNA of Trichomonas gallinae that had the identical size as the amplicon obtained with DNA from T. gallinarum. However, no PCR products resulted from any of the other samples tested with these primers. Liver and caecal samples from turkeys and chickens from flocks with outbreaks of histomonosis also named as "histomoniasis" originating from geographically distinct regions were investigated with the established PCRs. This is also the first report about the detection of the nucleic acid of H. meleagridis, T. gallinarum and Blastocystis spp. nucleic acid in the livers and/or caeca of laying hens and turkeys obtained from field outbreaks. Hence, the established PCR assays proved to be a rapid and sensitive diagnostic tool for the direct detection and differentiation of H. meleagridis, T. gallinarum and Blastocystis spp. nucleic acid in organ samples of infected turkeys and chickens regardless of the geographic origin.

Clonal cultures of Histomonas meleagridis, Tetratrichomonas gallinarum and a Blastocystis sp. established through micromanipulation

Clonal cultures of Histomonas meleagridis, Tetratrichomonas gallinarum and a Blastocystis sp. were established for the first time. Single microbes were successfully isolated from a mixture of micro-organisms obtained from caecal contents of turkeys, using a micromanipulation approach. The cloned parasites were propagated in vitro and maintained through continuous passages multiplying to high numbers. Identification of the protists was done by morphological investigation identifying various forms of each parasite. PCR and partial sequencing of the small subunit rRNA were used to confirm clonality and to determine the relationship of the cloned parasites with known protozoan parasites. The clonal cultures established by this technique will be useful to gain more insight into the biological repertoire of the organisms. In addition, refined infection experiments in different poultry species can now be performed to elucidate the pathological pathways of the respective protozoa.

Clostridium perfringens alpha toxin affects electrophysiological properties of isolated jejunal mucosa of laying hens

Bacteria that colonize the intestinal tract can invade epithelial cells or produce toxins that cause diarrhoeal diseases. Proliferation of Clostridium perfringens and production of alpha-toxin, a phospholipase C, is the major factor for necrotic enteritis in poultry. However, little is known about the functional importance of luminal alpha-toxin during intestinal infection. The purpose of this study was to investigate the effects of purified alpha toxin of Clostridium perfringens on the electrophysiology of the laying hen's stripped jejunum in Ussing chambers. The effects were investigated in Experiment 1 after toxin addition to the mucosal and serosal side of the tissue, and a second experiment was performed to study the effect of the toxin on sodium-dependent glucose transport. Mucosal exposure of jejunal tissue sheets to 100 units of alpha toxin/L did not elicit electrophysiologic changes. The addition of purified alpha toxin to the serosal side induced a biphasic increase in short-circuit current (ISC) after 15 and 100 min. The magnitude of the increase of ISC of both peaks was similar, but the second phase response lasted longer. The tissue conductivity tended (P = 0.07) to be lower after 2 h of toxin addition compared with basal value when no toxin was added. In the second experiment, adding D-glucose on the mucosal side of the jejunum increased (P < 0.05) the ISC from a baseline value of 42 +/- 28 microA/cm2 to a maximal value of 103 +/- 27 microA/cm2. Preincubation with alpha-toxin almost fully inhibited this stimulation of ISC by D-glucose. The conductance of the tissues was not affected by the toxin addition. These findings indicate that alpha toxin not only causes electrogenic secretion of anions, probably due to the stimulation of chloride secretion, but also diminishes electrogenic Na+/glucose cotransport from the mucosal to serosal side in the small intestine of poultry.

Cryptosporidium infection in domestic geese (Anser anser f. domestica) detected by in-situ hybridization

An in-situ hybridization (ISH) procedure was developed for the detection of Cryptosporidium sp. in paraffin wax-embedded tissues with a digoxigenin-labelled probe targeting the 18S rRNA. This technique was used in addition to traditional methods, such as haematoxylin and eosin staining, periodic acid-Schiff reaction, transmission electron microscopy and the polymerase chain reaction, to examine the bursa of Fabricius (BF), conjunctiva and other tissues from 20 domestic geese aged 16-36 days for the presence of cryptosporidia. Positive signals were found to a moderate or marked extent in both conjunctival samples (89%) and BF samples (88%) but not in other tissues. Sequencing of the PCR amplification product revealed identity with Cryptosporidium baileyi. The infected geese showed no clinical signs and only scanty histological lesions. These results confirm reports showing that young waterfowl are especially vulnerable to cryptosporidium infection and indicate that the BF and conjunctiva are the preferred sites for the presence of the protozoon. ISH proved a good method for detecting and identifying even small numbers of cryptosporidia in tissue sections.

Limited Pathogenicity of Usutu Virus for the Domestic Goose (Anser anser f. domestica) Following Experimental Inoculation

Usutu virus (USUV) is a mosquito-borne flavivirus of the Japanese encephalitis virus group, which has been associated with avian mortality in Austria since 2001. The affected birds are predominantly Eurasian blackbirds (Turdus merula). In the present study, the pathogenicity of USUV for domestic geese (Anser anser f. domestica) was investigated. Eleven 2-week-old geese were inoculated intramuscularly with 5 x 10(4) 50% tissue culture infectious dose of USUV strain Vienna-2001 blackbird. No clinical signs were seen during the observation period. Four inoculated and one in-contact geese died without preceding clinical signs. Two of the deaths could be attributed to bacterial septicaemia and strangulation, respectively. The cause of death of two experimental and one in-contact animals remained unclear, but lack of evidence for viral lesions and viral antigen in their tissues argued against association with the USUV infection. Although in organs of the majority of inoculated geese (9/11) USUV was detected by reverse transcriptase-polymerase chain reaction, immunohistochemistry for USUV antigen was negative in all tissues of all geese. Evidence of plasma viraemia or viral excretion was found in one goose only. Seroconversion was detected in three inoculated geese 10 days post-inoculation. Geese placed in contact with inoculated geese and control animals did not exhibit USUV in their internal organs or plasma and lacked USUV-specific antibodies. This experiment shows that USUV is able to replicate in geese, but does not induce clinical disease, is unlikely to induce mortality, and only infrequently leads to viraemia or virus shedding.

[Bright white vocal folds and capillary ectasias. Late sequelae after radiotherapy]

We report on visible laryngeal changes after radiotherapy. In this study, three women and two men aged 50-64 years were involved. In three cases, the primary tumor was a carcinoma of the thyroid gland and in one case a carcinoma of the esophagus. Due to dysplasia of the vocal folds, one patient underwent primary radiotherapy. Endoscopy was performed 4 to 22 years after radiotherapy. The larynx was examined by video-laryngoscopy and stroboscopy. We found a characteristic pattern of the vocal folds in all patients: bright white vocal fold surface, ectasia of capillaries and increased angiogenesis. We only found this pattern in patients after radiotherapy. In our opinion, these findings are late sequelae of radiotherapy. The picture of laryngitis due to radiotherapy can be distinguished from chronic laryngitis of other etiology using these criteria.

Einseitige auditorische Neuropathie

Auditory neuropathy presents with normal otoacoustic emissions combined with pathological findings in brainstem evoked response audiometry. Normally, the auditory neuropathy is bilateral. We report about a 9 year old child where we could diagnose a unilateral deafness in spite of regular TEOAE and DPOAE. No reproducible biosignals were seen when the right ear was stimulated with alternating click stimuli at a level of 80 dB. On the left side, the latency of the potentials was normal. A cranial MRI showed normal anatomy. In order to determine a unilateral deafness, objective tests (e.g., OAE, BERA) and subjective tests should be used.

Terminology of polymers containing ionizable or ionic groups and of polymers containing ions (IUPAC Recommendations 2006)

This document defines the terms most commonly encountered in the field of polymers containing ionizable or ionic groups and polymers containing ions. The scope of the document has been limited to organic polymers. Inorganic materials, such as certain phosphates, silicates, etc., which also may be considered ionic polymers, are excluded from the present document.

The terms selected are those that are widely used in the field of polymers containing ionizable or ionic groups and polymers containing ions. Only those terms that could be defined without ambiguity are considered.

The terms are listed in alphabetical order, and cross-references to definitions given in other documents are provided.

[Experiences with 'optical' biopsies of leukoplakia of the vocal folds]

BACKGROUND

It is often difficult to distinguish leucoplakia from carcinoma or chronic laryngitis. In this study, we examined if color texture optical biopsies are able to detect leukoplakia reliably and to distinguish this from normal vocal fold tissue.

METHODS

25 images from patients with a normal larynx and 25 images from patients with leucoplakia were analysed retrospectively. The images were recorded with a rigid 90 degrees -laryngoscope (Wolf Typ 4450.571) during a clinical setting and were recorded by a S-VHS-videorecorder. With a software program (InSegT), regions with leucoplakia, normal tissue and suspicious tissue were manually marked. Within each marked region, the use of color texture analysis numeric features were calculated to characterize the surface in texture and color. Color histogramms (HST), Sum- and Difference histogramms (S/D), Statistical Geometric Features (SGF) and Grey-Value-Dependent-Matrix (GLDM) were used.

PATIENTS

29 women and 21 men (age 18 to 81 years, average of 53 years), who were examined in our clinic from 10/1999 - 8/2003, took part in this study.

RESULTS

The automatized classification for color texture analysis resulted in 71 % for leucoplakia and 97 % for normal tissue.

CONCLUSION

Optical biopsies can contribute to find the correct diagnosis. However, classification results must still get better when optical biopsies should be used in clinical practice.

[Experiences with intraoperative application of prednisolone during Isshiki type I thyroplasty]

Laryngeal edema is considered a postoperative problem in phonosurgery. In a prospective study we examined if a single intraoperative application of prednisolone can decrease the incidence of postoperative laryngeal edema after Isshiki type I thyroplasty. We examined ten patients undergoing unilateral type I thyroplasty [seven men and three women, age range: 19-60 years (average: 48 years)]. In six patients we administered 250 mg prednisolone i.v. during surgery. In four patients no steroids were given at all. On the 1st and 2nd postoperative day, the larynx was examined in a clinical setting. Five of six patients who received intraoperative steroid medication had no postoperative laryngeal edema. Only in one of those patients we examined a small edema of the arytenoid region. In all four patients without steroid medication a postoperative edema of the ipsilateral arytenoid hump was seen. Thus, intraoperative intravenous steroid administration seems to prevent, or at least reduce, postoperative laryngeal edema. Only in one of those patients we examined a small edema of the arytenoid region.

Klinischer Einsatz der endolaryngealen Laservermessungstechnik

INTRODUCTION

Laser projection techniques have made morphometric measurement of laryngeal structures possible. The clinical application of a new laser measurement technique that uses a double reflecting mirror for laser beam duplication is discussed.

MATERIAL AND METHODS

Endolaryngeal measurement with a new two-point laser light projection method was carried out on 25 patients with ten different organic lesions of the vocal folds. The laser measurement tool can be clipped onto the shaft of a rigid endoscope. A special software program enables quick and precise measurements of distances and areas that are in the same horizontal plane as the laser spots.

FINDINGS

Using this new system, a clinical examination of the size of organic lesions of the vocal folds is possible, with a precise measurement of endolaryngeal structures being possible in all cases. The findings are easily documented, and the examinations can take place during routine laryngoscopic investigations.

CONCLUSION

Systems for endolaryngeal measurements enable morphometric measurements within the larynx. Quantitative examinations have become possible in laryngology.

Endolaryngeale Laservermessung - Von der Idee bis zur klinischen Anwendbarkeit

INTRODUCTION

In clinical and scientific examinations with rigid and flexible endoscopes quantitative morphometric measurements of intralaryngeal structures have been difficult whereas qualitative laryngoscopic examinations are routine procedures.

MATERIAL AND METHODS

The development of a two-point light projection method for endolaryngeal morphometry in its different phases is described. The way from a first prototype for endolaryngeal morphometry that works with a prism technique to the latest, most modern prototype, which works with a double reflecting mirror is shown.

RESULTS

In combination with a newly developed PC software the latest prototype for two-point laser-light projection enables an accuracy of 95 % to 99 % in the measurement of intralaryngeal distances. The contrast of the laser beams to the mucous membrane of the larynx could be optimized by the use of green--instead of red--laser light.

CONCLUSION

Morphological measurements within the larynx are now possible for clinical and scientific questions. Former limitations in quantitative morphometric examinations will be reduced.

Geschwindigkeitsmessung der Stimmlippenbewegung

INTRODUCTION

Clinical examinations with short-interval, color-filtered double-flash stroboscopy enable us to estimate the movements of the vocal fold edges during phonation. So-called 'displacement bands' show the degree of the vibratory amplitude in these images. Using the two-point light projection method the displacement bands can be measured with very high accuracy. A combination of these two methods was used for velocity measurements of the vocal fold movements within the phonatory cycle. The aim of the study was to explore the influence of change in sound pressure level (SPL) and fundamental frequency (F0) on the velocity of the horizontal amplitude of the vocal folds during phonation.

MATERIAL AND METHODS

40 healthy volunteers (31 women, 9 men, average age 24.8 years) were examined. During the special videostroboscopy with short-interval, color-filtered double flashes laser spots were projected onto the vocal folds by an endoscopic two-point light projection device. The subjects had to change their SPL and F0 following a test protocol. During phonation they had to produce tones in low, middle and high chest voice as well as in falsetto register. Each subject was asked to do this in a soft, a modal, a loud and a very loud manner. Images of the phonatory cycle showing the vocal folds immediately before collision were measured separately at three different positions. About 15,000 single measurements were evaluated.

RESULTS

The measured velocity of the horizontal amplitude during the closing phase of the vocal folds in chest voice was 30-160 cm/s. An increase in SPL resulted in an increasing velocity of the displacement bands. A change in F0 did not lead to statistically relevant changes in the measured velocity.

CONCLUSION

A combination of short-interval, color-filtered double-flash stroboscopy and a two-point light projection method enables measurements of the velocity of vocal fold movements. The SPL is the important factor for the velocity change within the phonatory cycle. F0 seems not to covary with the velocity of the horizontal amplitude during the closing phase of the phonatory cycle.

Hatchability, serology and virus excretion followingin ovovaccination of chickens with an avian metapneumovirus vaccine

The present investigation describes for the first time the effect of an avian metapneumovirus vaccine administered in ovo to 18-day-old chicken embryos. The application of the vaccine had no adverse effect on the hatchability or the health of the chicks post hatch. The antibody titres achieved were higher than those determined for birds vaccinated at 1 day old. Not only were the mean titres in the in ovo vaccinated groups higher, but many more birds developed a measurable antibody response than birds vaccinated at 1 day old. Variation of the vaccine dose used in ovo had little effect on the serological responses that peaked 21 to 28 days post hatch. Re-isolation of the vaccine virus was much more successful from birds vaccinated in ovo than from birds vaccinated at 1 day old, and detection of the nucleic acid by polymerase chain reaction correlated with the results of live virus isolation.

Accumulation of Mn(II) in Deinococcus radiodurans facilitates gamma-radiation resistance

Deinococcus radiodurans is extremely resistant to ionizing radiation. How this bacterium can grow under chronic gamma radiation [50 grays (Gy) per hour] or recover from acute doses greater than 10 kGy is unknown. We show that D. radiodurans accumulates very high intracellular manganese and low iron levels compared with radiation-sensitive bacteria and that resistance exhibits a concentration-dependent response to manganous chloride [Mn(II)]. Among the most radiation-resistant bacterial groups reported, Deinococcus, Enterococcus, Lactobacillus, and cyanobacteria accumulate Mn(II). In contrast, Shewanella oneidensis and Pseudomonas putida have high iron but low intracellular manganese concentrations and are very sensitive. We propose that Mn(II) accumulation facilitates recovery from radiation injury.

[Is there a consensus in the division of the vocal folds in thirds?]

INTRODUCTION

In clinical routine we have noticed a disagreement of ENT-specialists and phoniatricians in the division of the vocal folds in thirds. To show if there is consensus in this field by the german phoniatricians this study was done.

MATERIAL AND METHODS

In two parts of a study, a pilot study and a follow up study, we sent twelve different images of the larynx to all german phoniatricians. In six of these images the physicians should set the marks of the ventral and dorsal limitation of the second third of the vocal folds. In six different images a mark should be related to the particular third of the vocal folds. The phoniatricians were asked to assess how certain they were in their valuation. They were asked either, how long they have been working as a physician and how long they have been specialized as a phoniatrician and as an ENT-surgeon. In the follow up study the phoniatricians were requested to first divide up the thirds in a way that the dorsal third corresponds to the cartilaginous part of the vocal folds (scheme 1) and second divide up the thirds in a way that all three thirds correspond to the ligamental part of the vocal folds. DISCUSSION AND FINDINGS: In the pilot study, when no instructions for the division of the thirds were given, the data differed much more than in the follow up study, when the physicians were told to use scheme 1 and scheme 2. That was because some phoniatricians divided up just the ligamental part and others the ligamental plus the cartilaginous part of the vocal folds in thirds. The more the physicians could overlook the membraneous part of the vocal folds the more certain they were in their assessment.

CONCLUSION

The assessment of the division of the vocal folds in thirds is more homogeneous when the phoniatricians were requested to divide up the thirds in a way that the dorsal third corresponds to the cartilaginous part of the vocal folds (scheme 1). Therefore we suggest that this way of division should be used further on.

[Vocal cord dysfunction. An important differential diagnosis to bronchial asthma]

Vocal cord dysfunction (VCD) is described as a functional disorder of the vocal folds which leads to an intermittent, inspiratory 'paradoxical' glottal closure. We report on three women with frequent repetitive shortness of breath attacks caused by VCD. This was diagnosed by transnasal videofiberendoscopy, with glottal closure being seen during inspiration. Because of the different etiologies, one of the patients was treated with breathing and speech therapy, another received Omeprazol for laryngopharyngeal reflux, and the third was treated by intralaryngeal botulinum toxin injections. All three patients showed a reduction in attacks. Clinically, VCD seems to mimic asthma. However, with a thorough patient history and diagnostics, especially with transnasal laryngoscopy during a (triggered) attack, a precise diagnosis seems possible.

[Voice-improving laser-surgical therapy in amyloidosis of the larynx]

Laryngeal amyloidosis is relatively uncommon, accounting for only 0.2-1.5% of all laryngeal tumours. Hoarseness, dysphagia and stridor are potential clinical symptoms. A systemic amyloidosis should be excluded even though symptoms are only apparent in the head and neck region. For the localised form, surgical excision of the excess tissue is performed. We discuss the development of the disease, together with its diagnostics and therapy, based on the case report of a 42 year old female patient.

[Influence of the head position in laryngoscopy]

INTRODUCTION

The aim of this study was to determine the optimal position of the head during larygoscopy.

MATERIAL AND METHODS

During fiberoptic evaluation of the larynx, the head position of eight subjects (5 male, 3 female) was changed systematically. The influence of reclining and anteversion, tilting and rotation of the head on the quality of the endoscopic images was determined.

RESULTS

The vocal tract became wider and the view onto the glottis could be improved by reclining the head and anteversion of the chin. On rotation of the head, the hypopharynx of the same side became narrower. This is well known and is used worldwide in the therapy of dysphagia.

DISCUSSION

Positioning of the patient is important in laryngoscopy. Reclining the head and forward inclination of the trunk (horizontal axis of the mouth) seems to be the best position for obtaining an optimal view onto the glottis.

Ausgepr�gte beidseitige mesocochle�re Schwerh�rigkeit von 40?45�dB bei regelrechten TEOAE, DPOAE und unauff�lliger Click-BERA

An objective screening method for assessment of inner ear function of babies and small children can be carried out by measuring TEOAE and DPOAE. In particular, TEOAE can be used as a cheap and quick method to determine, with very high sensitivity and moderate specificity, whether middle to severe peripheral hearing impairment is present. In order to assess the threshold more precisely, the click-BERA is routinely used. We present a case report of a 6 year old girl with regular TEOAE and DPOAE, and who also had bilateral normal thresholds in the click-BERA. With subjective audiometry, the girl could be diagnosed having bilateral mesocochlear hearing impairment (so called cookie-bite audiogram) ranging at 40-45 dB. The child was helped considerably by fitting of hearing aids bilaterally. In order to determine the auditory ability of children and to provide adequate care, subjective as well as objective tests should be used.

Avian metapneumovirus excretion in vaccinated and non-vaccinated specified pathogen free laying chickens

Vaccinated and non-vaccinated specified pathogen-free White Leghorn laying chickens were challenged at peak of lay by the intravenous or oculonasal route with a virulent avian metapneumovirus (aMPV) subtype B chicken strain. Severe clinical signs and a drop in egg production were induced in the non-vaccinated intravenously challenged birds whereas the vaccinates were not affected. Live virus excretion was demonstrated in the faeces and respiratory tract of non-vaccinated hens for up to 7 days post intravenous challenge. After oculonasal challenge, virus excretion could only be demonstrated in the respiratory tract for up to 5 days. No live virus excretion was found in either the faeces or the respiratory tract of vaccinated birds. Concurrent with live virus isolation, the presence of viral RNA was demonstrated by single reverse transcription-polymerase chain reaction (RT-PCR). Nested RT-PCR was more sensitive and viral RNA could be detected in non-vaccinated birds up to 28 days post either intravenous or oculonasal challenge, at which time the experiment was terminated. Viral RNA was detected for up to 12 days in vaccinated birds. This is the first study investigating excretion of aMPV and viral RNA in vaccinated and non-vaccinated laying hens challenged under experimental conditions. The results are of importance with regard to the persistence of aMPV and the appropriate diagnostic detection method in laying birds.

Diagnostik von psychogenen H�rst�rungen im Kindesalter

In comparison with organic hearing loss, which is commonly reported, non-organic hearing loss is under-represented in the literature. The audiological results for 20 patients, aged between 6 and 17 years (mean 11.3), with psychogenic hearing disturbances were analysed prospectively. In 17 cases, the disturbance was bilateral and in three cases unilateral. In no case was the result of an objective hearing test exceptional, while a hearing threshold of between 30 and 100 dB was reported in single ear, pure-tone audiograms. In 12 cases, single ear speech audiograms were unexceptional. Suprathreshold tests, such as the dichotic discrimination test or the speech audiogram with noise disturbance, could lead to a clearer diagnosis in cases of severe psychogenic auditory impairment. In half of the patients, a conflict situation in the school or family was evident. After treatment for this conflict, hearing ability returned to normal. There was no improvement for six patients.

[Reinke edema--helpful in unilateral recurrent laryngeal nerve paralysis?]

We report on a 57-year-old teacher who consulted us for her known unilateral recurrent nerve paralysis subsequent to strumectomy. Video laryngoscopic and stroboscopic examinations revealed Reinke's edema in addition to the left-sided immobile vocal fold with maintenance of good vocal function. Because of the left-sided Reinke's edema, complete glottal closure was possible although the left vocal ligament remained slack. Surgical removal of the vocal fold edema in this case would presumably result in considerable impairment of vocal function. This example illustrates that in selected cases Reinke's edema can contribute to maintenance of phonation in unilateral vocal fold paralysis. In these cases, indication for edema surgery should be very restrictive and should always take the vocal function into consideration.

[Oropharyngeal vocal tract space during singing--comparison of tactile-kinesthetic and auditory perception with objective endoscopic findings]

BACKGROUND

In this study we compared the perceived diameter of the vocal tract's oropharyngeal part with the diameter that was determined endoscopically.

METHODS

28 singers (13 male, 15 female) were examined with transnasal fiberscopic pharyngoscopy while singing the vowels /a/, /i/ and /u/ in 4 different timbres (normal, opened, covered, dumpled) and 3 different pitches (chest/modal register, subjective comfortable pitch for singing, head/falsetto register). The tactile-kinesthetic and auditive rating of the singers, the auditive rating of a singing teacher and the visual-endoscopic analysis of three laryngologists were compared.

RESULTS

The tactile-kinesthetic and auditory self-perception of the singers was quite different from the auditive perception of a singing teacher and visual endoscopic findings of the laryngologists. The singers had the impression that the different singing timbres (normal, opened, covered, dumpled) influence oropharyngeal vocal tract space during singing. They judged the vowel itself and the pitch as having very little influence. Based on his auditory perception, the singing teacher also rated that the timbre plays an important role for the oropharyngeal vocal tract space but he found vowels to be the parameter with the greatest impact. Via visual endoscopic examination we found that, among the three parameters (vowel, timbre, pitch), the different vowels are most influential on the oropharyngeal vocal tract space. Analysis of video sequences revealed that pitch and timbre are less important.

CONCLUSION

Subjective tactile-kinesthetic and auditory perception of the singers differs from auditory perception of the singing teacher as well as from endoscopic findings. The endoscopically determined oropharyngeal vocal tract space during singing the vowels /i/ or /u/ tends to be larger compared to the oropharyngeal vocal tract space while singing the vowel /a/.

[Non-invasive screening for GJB2 mutations in buccal smears for the diagnosis of inherited hearing impairment]

BACKGROUND

Approximately 1 out of 1000 children is affected by severe or profound hearing impairment at birth. In the last years it has been shown that more than 50 % of inherited prelingual, sensorineural hearing impairment may be attributed to genetic defects. Most commonly, the GJB2 gene (chromosome 13q11) that encodes connexin 26 (Cx26) is affected. Cx26 is crucial for the formation of gap junctions which play an important role in the intercellular exchange of electrolytes. A variety of autosomal recessive GJB2 mutations associated with inherited hearing impairment has meanwhile been identified. The most common GJB2 mutation in Caucasian populations, 35delG accounts for the majority of cases and has a carrier frequency of more than 2.5 %. Other distinct mutations account for hearing impairment in other parts of the world.

MATERIAL AND METHODS

We examined in 59 Caucasian and Ghanaian individuals whether DNA recovered from buccal smears was appropriate for genetic testing by polymerase-chain reaction (PCR) based DNA-sequencing.

RESULTS

Buccal smears could be taken conveniently in all cases, even from small babies. In 53 out of 59 samples the material recovered from buccal smears could be subjected to PCR of the second exon of the GJB2 gene and subsequent DNA-sequencing. GJB2 mutations were identified in 34 patients. 13 Caucasian individuals exhibited the most common mutation 35delG. In addition, four cases of the rare W24X and each one heterozygous case of the V153I- and the L90P mutation were found. In two African individuals the 35insG mutation was detected. All other African patients had mutations exclusively identified in Ghana so far with the exception of R143W. R143W accounts for most cases of profound deafness in Ghana and has been identified in low frequencies in other ethnic groups as well.

CONCLUSION

Screening for GJB2 mutations in DNA recovered from buccal smears of individuals with inherited hearing impairment offers an easy, non-invasive method for early diagnosis and a basis of genetic counselling.

[Physical and technical elements of short-interval, color-filtered double strobe flash-stroboscopy]

INTRODUCTION

Quantitative measurement of vocal fold movements can be done either with high-speed imaging or with short interval, color-filtered double strobe flash-stroboscopy. The physical and technical elements of this new technique are described.

METHODS

Two special strobe units (KAY Elemetrics RLS 9100) are used in a master-slave configuration. In this way an adjustable interval of 0.1-2.0 ms between flashes is introduced. The strobe flashes are color filtered and are separated by a brief interval. By this means a double exposure is created in each video frame.Real-time visualization of opening and closing velocities over the entire length of the vocal fold from anterior to posterior is possible. Quantification is possible off-line after image calibration.

CONCLUSION

Short-interval, color-filtered double-strobe flash stroboscopy allows quantitative measurement of the velocity of vocal fold movements during vibration at different pitches and sound pressure levels (SPL). Images gained with this new technique provide information about a dynamic property (velocity) of the vocal fold within a single image.Therefore, its use could be helpful from the aspect of clinical documentation.

The use of PCR combined with restriction enzyme analysis to characterize fowl adenovirus field isolates from northern India

Ten fowl adenoviruses (FAVs), isolated from suspected cases of inclusion body hepatitis (IBH) in quails and broilers, were characterized by a hexon-based polymerase chain reaction (PCR) combined with restriction enzyme analysis (REA) of the amplified DNA fragments. All the isolates could be detected using H1/H2 and H3/H4 primer sets. Amplification of DNA with H1/H2 and H3/H4 primer sets resulted in fragments of approximately 1219 bp and 1319 bp, respectively. HaeII digestion of the H1/ H2 PCR products and HpaII digestion of the H3/H4 PCR products characterized all the isolates in FAV groups, known from genomic typing using the whole DNA. For some of the isolates, neutralization tests were used to confirm these results. The results revealed that, as well as FAV serotype 1, which is the sole member of DNA group A, FAVs of DNA group E are also associated with IBH in poultry in northern India. The FAV specific PCR combined with REA was found to be very useful in investigating the epidemiological situation in the field. It was even possible to define mixed infections with more than one FAV.

The pattern of cone pedicles and horizontal cells in the retina of the European anchovy, Engraulis encrasicolus L. (Engraulididae, Clupeiformes)

We have studied the architecture of polycone pedicles and their postsynaptic horizontal cells in the European anchovy using serial reconstruction by means of thin-sections from the cone outer segments to the outer plexiform layer. Within this layer there is a tesselated arrangement of pedicles in two strata, one made by the long-cone pedicles and one by those of the short-cones. The two pedicle types differ in the architecture of their synaptic sites. The long-cones possess two ribbon clusters corresponding to two bunches of subsynaptic dendrites, while the short-cones have only a single ribbon cluster innervated by a single group of dendrites. In addition, telodendria specifically connect the cone pedicles of neighbouring rows. Among the horizontal cells three classes arranged in separate levels can be distinguished. Serial reconstruction results suggest that first level horizontal cells contact long-cones preferentially. Among bipolar cells with an oval shaped dendritic field another type is found with a rectangular field of polycone-parallel dendritic combs. These findings indicate that the uncommon cone structures of engraulidids, which probably subserve polarization contrast vision, are correlated with a peculiar geometry of the outer plexiform layer.

Inhibition of human natural killer cell activity by cereulide, an emetic toxin from Bacillus cereus

The lipophilic toxin, cereulide, emitted by emetic food poisoning causing strains of Bacillus cereus, is a powerful mitochondria toxin. It is highly lipophilic and rapidly absorbed from the gut into the bloodstream. We tested how this toxin influences natural killer (NK) cells, which are important effectors in defence against infections and malignancy. Cereulide inhibited cytotoxicity and cytokine production of natural killer cells, caused swelling of natural killer cell mitochondria, and eventually induced natural killer cell apoptosis. The suppressive effect on cytotoxicity was fast and toxic concentration low, 20-30 microg/l. As the emesis causing concentration of cereulide is around 10 microg/kg of total body mass, our results suggest that emesis causing or even lower doses of cereulide may also have a systemic natural killer cell suppressive effect.