Biomedical subjects

M Hess

Publications and source records attributed to M Hess.

At least 91 records · Page 5Linked to original sources

PubMed1999

PCR for specific detection of haemorrhagic enteritis virus of turkeys, an avian adenovirus.

A hexon gene based PCR was developed for specific amplification of DNA sequences from the haemorrhagic enteritis virus (HEV) of turkeys. The hexon genes of different avian adenoviruses were compared for primer construction. Two regions with low sequence homology between HEV and fowl adenovirus (FAV) hexon genes were selected for primer localisation. In correlation with the known sequence data a fragment of 1647 bp was amplified from a live vaccine and spleens of turkeys suffering from haemorrhagic enteritis (HE). All other avian adenoviruses which are able to infect turkeys, i.e. FAV and turkey adenoviruses (TAV), were negative. This is the first PCR for specific detection of HEV DNA which should be useful for rapid diagnosis and epidemiological investigations of HEV infections in turkeys.

Animals↗

PubMed1999

Mode switching in dual chamber pacemakers: effect of onset criteria on arrhythmia-related symptoms.

AIMS: Various mode-switching algorithms are available with different tachyarrhythmia detection criteria to be satisfied to initiate mode-switching. This study evaluated three different mode-switching algorithms in patients with paroxysmal atrial fibrillation. METHODS AND RESULTS: Seventeen patients completed the study. Three mode-switching algorithms were downloaded as software into the pacemaker, each for 1 month in a single-blind, randomized sequence. The criteria to initiate mode-switching were: mean atrial rate ('standard'), '4-of-7' or '1-of-1' atrial intervals to exceed the atrial detection rate. Symptoms for each were measured using the Symptom Checklist Frequency and Severity index. The median number of mode-switch episodes increased from 20 for 'standard' to 39 for '4-of-7' (P=0.029 vs 'standard') and 103 for '1-of-1' (P=0.0012 vs 'standard') onset criteria. Median duration of episodes decreased from 2.5 min with 'standard' to 1.4 min with '4-of-7' and 0.4 min with '1-of-1' onset criteria. Frequency of symptoms was lower using '4-of-7' (18.2 +/- 12.0 vs 23 +/- 12.0, P=0.08) or '1-of-1' (20.4 +/- 12.4 vs 23 +/- 12.0, P=0.07) than 'standard' onset criteria. Severity of arrhythmia tended to be less with either '4-of-7' (16 +/- 10.4 vs 19.1 +/- 19.4, P=0.12) or '1-of-1' (17.5 +/- 10.3 vs 19.1 +/- 9.4, P=0.18) than with 'standard' onset criteria. CONCLUSIONS: The more sensitive onset criteria for detection of atrial tachyarrhythmias were associated with lower frequency and severity of symptoms.

Algorithms↗

PubMed1999

Physical assignment of the bovine MHC class IIa and class IIb genes.

Screening of a bovine yeast artificial chromosome (YAC) library revealed two clones which contain most of the class II genes of the major histocompatibility complex (MHC) known to date. The YACs were mapped by fluorescence in situ hybridization (FISH) and characterized for the class II genes they contain. We found that the classic class II genes BoLA- DQA, -DQB, -DRA, and -DRB3 are located at BTA 23q21 and the non-classic class II genes DYA, DIB, LMP2, LMP7, TAP2, BoLA-DOB, -DMA, -DMB, and -DNA are located at BTA 23q12-->q13. These two different mapping locations confirm and extend previous findings of a gross physical distance between classic and non-classic MHC class II genes in cattle.

Animals↗

PubMed1998

Hearing screening in at-risk neonate cohort.

OBJECTIVE: This prospective study reports on the prevalence of hearing impairment in an at-risk neonatal intensive care unit (NICU) population. DESIGN: From 1990 to 1997, 942 neonates were screened with transient evoked otoacoustic emissions (TEOAE) and brainstem evoked response audiometry (BERA). RESULTS: 835 Infants passed the primary screen for both ears, 57 for one ear, adding up to 94.7%. Seventeen infants (1.9%) were lost to follow-up. In thirteen infants (1.4%), bilateral hearing impairment above 30 dB was confirmed. While all children with hearing impairment belonged to the group of 820 children receiving aminoglycosides, only one presented no other risk factors. In 11 of the hearing impaired children other anamnestic factors, i.e. dysmorphism, prenatal rubella or cytomegaly, family history of hearing loss or severe peri- and postnatal complications seem to be more probable causes of the identified hearing loss. CONCLUSIONS: From our data, aminoglycosides seem not to be an important risk factor for communication related hearing impairment, when serum levels are continuously monitored, as occurred in our cohort. After adjustment for other risk factors, birth weight between 1000 and 1500 g and a gestational age between 29 and 31 weeks were no predictive markers for hearing impairment. It might be speculated that the improved medical treatment in a Neonatal Intensive Care Unit (NICU) reduces the probability of hearing impairment for those two groups. Conductive hearing loss as a possible additional cause for hearing impairment was not studied in detail, but the high percentage of malformations detected (four out of 13 hearing impaired infants) demands further monitoring, close follow-up, counselling and adequate treatment.

Acoustic Stimulation↗

PubMed1998

Nuclear Magnetic Resonance Detection of Two Distinctly Different Chains in the Orthorhombic Crystalline Phase of Polyethylenes.

Several commercial and noncommercial, high- and low-density and ultraoriented polyethylene samples, as well as polyethylene samples with inorganic fillers, have been investigated by inversion-recovery cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (NMR). In all these samples two types of all-trans chains in orthorhombic crystalline domains are detected, which give two overlapping carbon-13 lines with different line widths and different relaxation times. From the NMR relaxation parameters we conclude that one type of the crystalline chains, which composes 60-90% of the crystalline fraction in all samples, can execute at room temperature 180 degrees flips with a frequency in the kilohertz domain. The other crystalline chains are more rigid and probably are found in more perfect structures in which such chain flips do not occur or occur on a much slower time scale. Adding kaoline filler particles to polyethylene enhances the contribution of the more mobile crystalline chains. The presence of the two distinctly different types of crystalline environments is found in all polyethylene samples investigated so far (more than 25 samples).

Journal Article↗

PubMed1998

[Data protection for the national German Central Registry of Pediatric Hearing Disorders].

The German Registry for Hearing Loss in Children (DZH) processes nationwide data from audiological centers. Coping with the accrued data and its subsequent management and analysis requires a high degree of security and control. To establish a nationwide registry it is necessary at an early stage to take into consideration the legal requirements of the participating states. Use of the DZH as an example demonstrates how a pragmatic solution can be reached. Special issues concerning data collection, transfer, storage and deletion, coding strategies to ensure anonymity, checking for duplicate entries, data separation, and automated data analysis and data protection are explained.

Adolescent↗

PubMed1998

[Is diagnosis of persistent pediatric hearing loss still made too late?].

Since 1994, the German Registry for hearing Loss in Children has registered data of 1500 children and by now can present results concerning the age at diagnosis of permanent hearing loss in children in Germany. The mean age at diagnosis is still very high. There is a strong correlation between age at diagnosis and degree of hearing loss, i.e., severe and profound hearing loss, is diagnosed distinctly earlier than mild and moderate hearing loss. On average, mild hearing loss is diagnosed with 6.2 years, moderate h.l. with 4.4 years, severe hearing loss with 2.5 years and profound hearing loss with 1.9 years. This corresponds with the results of regional German studies. At least regionally, in other European countries the age at diagnosis is known to be distinctly lower. In 36% of the children registered in Germany the delay between first suspicion and diagnosis of permanent hearing loss is 1 year or more.

Age Factors↗

PubMed1998

Hexon based PCRs combined with restriction enzyme analysis for rapid detection and differentiation of fowl adenoviruses and egg drop syndrome virus.

Three different polymerase chain reactions (PCRs), two of them combined with restriction enzyme analysis (REA), were developed for detection and differentiation of all 12 fowl adenovirus (FAV) serotypes and the egg drop syndrome (EDS) virus. For primer construction FAV1, FAV10 and EDS virus hexon proteins were aligned and conserved and variable regions were determined. Two primer sets (H1/H2 and H3/H4) for single use were constructed which hybridize in three conserved regions of hexon genes. Each primer pair amplifies approximately half of the hexon gene including two loop regions. An amplification product was detected with both primer sets using purified DNA from all FAV1-12 reference strains. Viral EDS DNA was negative using the H1/H2 or H3/H4 primer pair. HaeII digestion of the H1/H2 amplification products differentiates between all viruses except FAV4 and FAV5. In comparison, much more clustering among genomic closely related FAV serotypes was seen after HpaII digestion of the H3/H4 PCR products. Oligonucleotides H5/H6 located in the variable regions of EDS virus hexon gene do not detect any of the FAV serotypes. The PCRs and REA described are suitable to detect all avian adenoviruses infecting chickens, to distinguish all 12 FAV reference strains and to differentiate FAVs from the EDS virus.

Adenoviridae Infections↗

PubMed1998

Correspondence of electroglottographic closed quotient to vocal fold impact stress in excised canine larynges.

The purpose of this study was to explore the possible use of the electroglottographic closed quotient (EGG CQ) as a noninvasive estimate of vocal fold impact stress (SI). Two excised canine larynges were used. Each larynx was mounted and vocal fold oscillation was induced using a humidified air source. Twenty-seven experimental trials were conducted for each larynx. Trials involved variations in vocal process gap, vocal fold elongation, and subglottic pressure. Simultaneous measures were made of vocal fold SI at the midpoint of the membranous vocal folds, and EGG CQ (dimensionless ratio). The results indicated that when threshold and saturation effects were excluded, the SI and the CQ were strongly related (linear correlation r = .83 and .96 for the two individual larynges, and .81 for the combined data). Within the region of linear relation, an increase of.15 in the CQ corresponded to about 1 kPa increase in SI for the combined data. Discussion focuses on possible clinical implications and the likely reasons for threshold and saturation phenomena.

Animals↗

PubMed1998

Molecular characterization of an autoallergen, Hom s 1, identified by serum IgE from atopic dermatitis patients.

Atopy is a genetically determined disorder that affects 10%-20% of the population. Many symptoms of patients with atopy (allergic rhinitis, conjunctivitis, asthma, and anaphylaxis) result from events occurring after crosslinking of cell-bound IgE by per se innocuous environmental antigens. The frequently raised hypothesis that autosensitization can also be a pathogenetic factor in atopy, gained support by our recent demonstration of IgE antibodies against human proteins in atopic dermatitis patients. To unravel the molecular nature of IgE-defined autoantigens, we used serum IgE from atopic dermatitis patients to screen a human epithelial cDNA expression library. One of the cDNA-encoding IgE-reactive products contained 1501 bp of a 2274 bp open-reading frame finally identified by sequence analysis of two additional cDNA clones resulting from oligonucleotide screening. The IgE-defined autoantigen, designated Hom s 1, exhibited an almost complete sequence identity with a recently described antigen recognized by cytotoxic T cells of a squamous cell carcinoma patient. Purified recombinant Hom s 1 specifically bound IgE from patients with severe atopy. When used as immunogen in rabbits, recombinant Hom s 1 gave rise to an anti-serum that reacted with a cytoplasmic protein exhibiting a broad cellular and tissue reactivity (skin, lung >> gastrointestinal tract >> muscle, brain) and identified a 55 kDa protein in blotted serum IgE preparations. The attractive possibility remains that the Hom s 1-triggered IgE response contributes to the events resulting in allergic tissue inflammation. If so, the respective recombinant molecule may serve as a paradigmatic tool for the diagnosis and treatment of patients with "intrinsic" atopy.

Allergens↗

PubMed1998

Localized primary non-Hodgkin lymphoma of the breast.

A single institution's experience with the treatment of localized primary lymphoma of the breast (PLB) was analyzed to understand the natural history of this disease and to identify major prognostic factors and optimal treatment. A retrospective analysis of 23 previously untreated patients who met the strict criteria of PLB from 1972 through 1994 was undertaken. All pathologic materials were reviewed and classified by the Working Formulation. The Ann Arbor stages (AASs) were: IE, 17 patients; IIE, five patients; IV, one patients (bilateral breast involvement without distant metastasis). Pathologic findings were: low grade, two patients; intermediate grade, 18 patients (17 with diffuse large-cell lymphoma (DLCL)); high grade, two patients; and unclassifiable, one patient. The treatments after biopsy or mastectomy were: radiation alone, two patients; chemotherapy alone, six patients; and combined-modality therapy, 13 patients. Two patients had mastectomy alone. Overall survival (OS) and relapse-free survival (RFS) were calculated actuarially. Univariate analyses were performed with patient age, treatment modality, AAS, size of the primary tumor (T stage), and International Prognostic Index (IPI) for the 17 patients with DLCL to define prognostic factors. The median follow-up for the surviving patients was 78 months (range, 45-220 months). The 5-year OS and RFS were 74% and 73%, respectively for all 23 patients, and 65% and 70%, respectively, for the 17 patients with DLCL. Statistically significant factors for OS for DLCL were AAS and IPI. Statistically significant factors for RFS were AAS and T stage. With modern staging evaluation and multiagent combination chemotherapy, localized primary non-Hodgkin lymphoma of the breast, especially diffuse large-cell type, has a prognosis as favorable as that of other DLCL. Ann Arbor stage was a significant factor for both OS and RFS.

Adolescent↗

PubMed1998

Is the atrial high rate episode diagnostic feature reliable in detecting paroxysmal episodes of atrial tachyarrhythmias?

The atrial high rate episode diagnostic in the Thera pacemaker reports frequency, duration, and date/time of atrial tachyarrhythmias according to programmed criteria. The aim of the study was to validate the atrial high rate episode diagnostic feature. Episodes of atrial fibrillation recorded by Holter monitoring were compared to episodes detected by the pacemaker. Forty five ambulatory (Holter) recordings were used for evaluation. Thirty of 45 ambulatory (Holter) recordings showed sinus rhythm. On 4 of these 30 ambulatory (Holter) recordings, the Thera detected 12 episodes of atrial tachyarrhythmias as false-positives (sinus rhythm was detected as atrial tachyarrhythmia). The main reason was far-field R and T was oversensing. On 15 of 45 ambulatory (Holter) recordings, 125 episodes of atrial tachyarrhythmias were recorded. Ninety-three of these events also were detected by the pacemaker, while for 32 events the Thera reported sinus rhythm. The main reason was that the episodes were of too short duration. Therefore, the Thera (programmed with detection rate 160 beats/min, detection beats 40, termination beats 10) was unable to detect atrial tachycardias. Software simulation of the diagnostic algorithm under several programming settings using the digitized Holter files demonstrated highly reliable detection of atrial tachyarrhythmias (sensitivity 98%, specificity 100%) when programmed as follows: detection rate 220 beats/min, detection beats 10, termination beats 20. It can be concluded that Thera's high rate episode monitor is a reliable tool for detection of atrial tachyarrhythmias, if programmed as recommended.

Aged↗

PubMed1998

Characterization of the rolipram-sensitive, cyclic AMP-specific phosphodiesterases: identification and differential expression of immunologically distinct forms in the rat brain.

To determine the properties of the cAMP-specific, rolipram-sensitive phosphodiesterases (cAMP-PDEs) that are expressed in different organs, monoclonal and polyclonal antibodies were raised against different epitopes present in the cAMP-PDE sequences. Of the several antibodies generated against peptides and fusion proteins, one monoclonal and four polyclonal antibodies recognized both the native cAMP-PDEs as well as the denatured proteins on Western immunoblot analysis. An immunoprecipitation assay demonstrated that these antibodies recognized the recombinant rat PDE4A, PDE4B, and PDE4D proteins with different avidity. The polyclonal antibody K118 and the monoclonal M3S1 were most specific for rat PDE4B and PDE4D forms, respectively, whereas the AC55 antiserum displayed the highest affinity for PDE4A forms. This selectivity was confirmed by Western blot analysis using recombinant rat PDE4A, PDE4B, and PDE4D proteins expressed in a heterologous system. These antibodies were used to characterize the cAMP-PDEs expressed in the rat brain. An immunoblot of extract of cortex and cerebellum demonstrated that at least seven different polypeptides specifically cross-reacted with the different antibodies, indicating that multiple cAMP-PDEs are expressed in this tissue. On the basis of cross-reactivity with PDE4D but not PDE4A or PDE4B antibodies, 93- and 105-kDa PDE4D species were detected in the cortex and cerebellum extract. These forms are different from the 68-kDa PDE4D form expressed in endocrine cells after hormonal stimulation. Although the 93-kDa form was recovered in both the soluble and particulate fractions, the 105-kDa polypeptide was mostly particulate in the cortex and cerebellum extracts. PDE4B forms of 90-87 kDa were recovered in both soluble and particulate compartments of the brain extract. These forms were different from the previously identified PDE4A variants of 110 and 75 kDa. These data demonstrate that the presence of multiple cAMP-PDE genes is translated into cAMP-PDE proteins of different sizes and distinct immunological properties and that multiple variants derived from these cAMP-PDE genes are expressed in different regions of the brain and different subcellular compartments. These immunological tools will be useful to identify different cAMP-PDE forms expressed in organs targeted for pharmacological intervention with PDE4 inhibitors.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1998

Genetic and biochemical analysis of mutacin 1140, a lantibiotic from Streptococcus mutans.

Streptococcus mutans JH1000 and its derivatives were previously shown (J. D. Hillman, K. P. Johnson, and B. I. Yaphe, Infect. Immun. 44:141-144, 1984) to produce a low-molecular-weight, broad-spectrum bacteriocin-like inhibitory substance (BLIS). The thermosensitive vector pTV1-OK harboring Tn917 was used to isolate a BLIS-deficient mutant, DM25, and the mutated gene was recovered by shotgun cloning in Escherichia coli. Sequence analysis of insert DNA adjacent to Tn917 led to the identification of four open reading frames including two (lanA and lanB) which have substantial homology to the Staphylococcus epidermidis structural gene (epiA) and a modifying enzyme gene (epiB) for biosynthesis of the lantibiotic epidermin, respectively. Although the BLIS activity could not be recovered from broth cultures, high yields were obtained from a solid medium consisting of Todd-Hewitt broth containing 0.5% agarose that was stab inoculated with JH1140 (a spontaneous mutant of JH1000 that produces threefold-elevated amounts of activity). Agar could not substitute for agarose. Chloroform extraction of the spent medium produced a fraction which yielded two major bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The faster-migrating band was absent in chloroform extracts of the mutant, DM25. The amino acid sequence of this band was determined by Edman sequencing and mass spectroscopy. The results showed that it is a lantibiotic, which we have named mutacin 1140, and that the sequence corresponded to that deduced from the lanA sequence. We observed a number of similarities of mutacin 1140 to epidermin and an S. mutans lantibiotic, B-Ny266, but it appears to have significant differences in the positions of its thioether bridges. It also has other unique features with regard to its leader sequence and posttranslational modification. A proposed structure for mutacin 1140 is presented.

Amino Acid Sequence↗

PubMed1998

Isolation of fowl adenoviruses serotype 4 from pigeons with hepatic necrosis.

Nine homogenized livers were taken to isolate the causative agent of adenovirus type I and type II infections in pigeons. The samples were passaged up to four times on primary chicken embryo hepatocytes. Adenoviruses were isolated from all of the six type II but none of the three type I infections. Serologically the isolated adenoviruses were classified as fowl adenovirus (FAV) serotype 4. Restriction enzyme analysis of two isolates in comparison with FAV4 reference strain KR5 confirmed the serological results and classification of the pigeon isolates as FAV4 strains.

Adenoviridae Infections↗

PubMed1998

[Adenovirus infections in psittacines].

Diagnostic investigations were carried out in a fatal disease of several African Grey Parrots (Psittacus erithacus) and Cape Parrots (Poicephalus robustus) in a large breeding plant. Electron microscopically examination of liver and intestine, the organs with the most prominent pathomorphological changes, regularly revealed adenoviruses. Necrotizing hepatitis and catarrhal to haemorrhagic enteritis dominated on histopathological examination. Numerous basophilic intranuclear inclusion bodies in hepatocytes and enterocytes and their ultrastructural characteristics underline the etiological role of the detected adenoviruses. Adenoviruses were isolated from livers of three different birds and once from the intestine. Serologically the isolates were classified as fowl adenovirus serotype 4 (FAV4). Restriction enzyme analysis of two isolates showed the identity with the FAV4 reference strain KR5.

Adenoviridae Infections↗

PubMed1997

The complete nucleotide sequence of the egg drop syndrome virus: an intermediate between mastadenoviruses and aviadenoviruses.

The complete nucleotide sequence of an avian adenovirus, the egg drop syndrome (EDS) virus, was determined. The total genome length is 33,213 nucleotides, resulting in a molecular weight of 21.9 x 10(6). The GC content is only 42.5%. Between map units 3.5 and 76.9, the distribution of open reading frames with homology to known genes is similar to that reported for other mammalian and avian adenoviruses. However, no homologies to adenovirus genes such as E1A, pIX, pV, and E3 could be found. Outside this region, several open reading frames were identified without any obvious homology to known adenovirus proteins. In the region organized similarly as other adenoviral genomes, most homologies were found to an ovine adenovirus (OAV strain 287). The highest level of amino acid identity was found for the hexon proteins of EDS and OAV. The virus-associated RNA (VA RNA) was identified thanks to the homology with the VA RNA of fowl adenovirus serotype 1 (FAV1). Similarities with FAV1 were also found in the fiber protein. Our results demonstrate that the avian EDS virus represents an intermediate between mammalian and avian adenoviruses. The nucleotide sequence and genomic organization of the EDS virus reflect the heterogeneity of the aviadenovirus genus and the Adenoviridae family.

Adenoviridae↗

PubMed1997

Uncoupling of XB/U-cadherin-catenin complex formation from its function in cell-cell adhesion.

Xenopus XB/U-cadherin forms functional complexes with mouse alpha- and beta-catenins and p120(cas) when expressed in murine L-TK- fibroblasts. These cells were stably transfected with cDNAs encoding different cytoplasmic XB/U-cadherin mutants, each partially deleted in the different parts of the 38 most carboxyl-terminal amino acids. The binding of p120(cas) was not affected by carboxyl-terminal deletions, confirming its binding to a region more amino-terminal and distinct from the catenins. alpha- and beta-catenins associate with truncated XB/U-cadherins if either 19 amino acid half of the cadherin 38 amino acid tail is present, indicating that the site of catenin interaction is upstream of the deletions. However, for adhesive function of XB/U-cadherin constructs, the most carboxyl-terminal 19 amino acids are essential; if these amino acids are deleted, cadherin-catenin complexes unable to mediate cell-cell adhesion are formed. Nonadhesive complexes are solubilized by mild detergent, whereas functional complexes are stable. Provided that detergent stability of cadherin-catenin complexes is taken as a measure of their cytoskeletal association, our results give first evidence that cytoskeletal stabilization occurs independent of cadherin-catenin complex formation and requires the 19-amino acid cadherin carboxyl terminus.

Amino Acid Sequence↗