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Biomedical subjects

M Hess

Publications and source records attributed to M Hess.

At least 19 recordsLinked to original sources
PubMed2007

[Glottal and supraglottal configuration during whispering].

BACKGROUND: The purpose of the study was to assess glottal and supraglottal configurations during whispering in comparison to habitual phonation and to visually estimate to what extent force is exerted onto the vocal fold epithelium during whispering. Is whispering a good compromise between preservation of epithelium and permission to communicate orally, e. g. postoperatively? PATIENTS AND METHODS: We investigated on 100 patients with organic or non-organic voice disorders. Patients with vocal fold immobility and patients with organic lesions large enough to impede glottal closure were excluded. Videolaryngoscopy and stroboscopy was performed via flexible endoscopy. During fiberoscopy the patients were asked (i) to phonate and then whisper a series of vowels in various loudness levels and (ii) to count to 10 voiced and whispered in various loudness levels. The extent of vocal fold adduction and supraglottal configuration were assessed and whispering compared with voiced phonation. RESULTS: Interindividual differences in glottal and supraglottal configuration during whispering were seen. The two different and most frequently seen glottal area patterns were determined by the position of the vocal processes - either adducted or abducted. Adduction resulted in sole cartilaginous triangle formation or 'kissing processes', abduction in ligamentous and cartilaginous triangle. Another surprising result was that with increasing loudness either a narrowing or widening of glottal and supraglottal structures was visible. CONCLUSIONS: There are different patterns of glottal and supraglottal configuration during whispering. Although the vocal folds can show partial or total contact over the membranous parts, the lack of additional vibration of the vocal folds suggests that epithelial forces are smaller than with additional vibratory shear stress. Thus, whispering may be considered and allowed for postoperative communication purposes, when patients follow instructions for low-effort whispering.

Adult↗
PubMed2006

In-situ hybridization for the detection and identification of Histomonas meleagridis in tissues.

For use in an in-situ hybridization method, three probes (HM, TR and BL) were designed to hybridize, respectively, with (1) Histomonas meleagridis, (2) Tetratrichomonas gallinarum, and (3) a broad range of micro-organisms, including Blastocystis spp. Mono-eukaryotic cultures were used to test the specificity of the three oligonucleotides and to optimize the hybridization procedure before applying the probes to archived samples of various tissues and to a culture of Trichomonas gallinae. Specific detection of H. meleagridis was possible with the HM probe, but the other two probes were less specific. The TR probe detected members of the Trichomonadidae (Tetr. gallinarum and Tr. gallinae). Positive signals from a great variety of microorganisms, including fungi and protozoa from different animal species, were obtained with the BL probe. However, neither H. meleagridis nor the two members of the Trichomonadidae mentioned above were detected with this probe, allowing the exclusion of these parasites. Use of the three probes makes possible the accurate detection of H. meleagridis and its distinction from other micro-organisms in tissue samples.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

[Unilateral auditory neuropathy. A rare differential diagnosis of unilateral deafness].

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.

Auditory Diseases, Central↗
PubMed2006

[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.

Adenocarcinoma, Follicular↗
PubMed2006

[The significance of videostroboscopy in laryngological practice].

The assessment of laryngeal pathology and voice dysfunction requires knowledge of anatomy and physiology as well as thorough understanding of the biomechanical (non)linear behaviour of vocal fold vibration. Videostroboscopy adds useful information to voice assessment, which always includes perceptual voice assessment and endoscopy of the larynx. Videostroboscopy can help in differentiating between benign vocal fold lesions, invasive processes, vocal fold scarring and functional disorders. Videostroboscopic evaluation can be improved by using different endoscopes and specific evaluation manoeuvres.

Germany↗
PubMed2006

Rapid transmission of the protozoan parasite Histomonas meleagridis in turkeys and specific pathogen free chickens following cloacal infection with a mono-eukaryotic culture.

In the present investigation, the pathogenicity and transmission of a mono-eukaryotic culture of Histomonas meleagridis for commercial turkeys and specific pathogen free (SPF) chickens is described for the first time. Two separate trials with the same kind of experimental design were performed, one with commercial turkeys and one with SPF chickens. In each experiment, two different groups were included, which were housed in separate rooms. The first group contained four control birds, whereas the second group consisted of 10 infected and four in-contact birds. The birds were infected via the cloaca at 14 days of age with 380,000 cells of a mono-eukaryotic culture of H. meleagridis consisting of a cloned isolate (Turkey/Austria/2922-66/04). Reisolation of the parasite from turkeys and chickens under experimental conditions was performed for the first time. The infected birds started to excrete the parasite as soon as 2 days post infection. Rapid spread of the parasite to in-contact turkeys and chickens was noticed, based on reisolation of live parasites. Reisolation of the pathogen was impossible from two of the four in-contact SPF chickens at any time, whereas all of the infected turkeys were found positive. Intermittent shedding of the parasite was noticed in infected turkeys and SPF chickens, but the phenomenon was much more severe in the SPF chickens as these birds survived the infection. All of the infected and in-contact turkeys died between days 11 and 14 post infection, whereas no death was recorded in the SPF chickens, which were killed 6 weeks after the infection. Typical lesions were recorded in the caeca and livers of the infected turkeys. In addition, a heavy destruction of the bursa of Fabricius was seen in all of the infected and one of the in-contact turkeys. Altogether, the present investigations are of importance for an understanding of the pathogenicity and transmission of H. meleagridis in poultry.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

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.

Animals↗
PubMed2005

[Clinical application of the endolaryngeal laser measurement technique].

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.

Endoscopy↗
PubMed2005

[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.

Adult↗
PubMed2005

[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.

Adolescent↗
PubMed2005

[Endolaryngeal distance measurement by laser light projection--from the idea to clinical application].

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.

Equipment Design↗