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Biomedical subjects

A Meyer

Publications and source records attributed to A Meyer.

At least 127 records · Page 7Linked to original sources
PubMed2000

Lupus erythematosus associated with genetically determined deficiency of the second component of the complement.

BACKGROUND: The gene deletion responsible for the type I human complement C2 deficiency was reported in 1992. The purpose of our study is to evaluate clinical and immunological characteristics of 11 patients with lupus erythematosus and type I C2 deficiency. OBSERVATIONS: We observed 5 patients with a homozygous C2 deficiency and 6 with a heterozygous C2 deficiency. Eight patients had systemic lupus erythematosus, 2 had subacute cutaneous lupus erythematosus, and 1 had chronic lupus erythematosus. Photosensitivity was present in 73% of the patients, and 64% tested positive for anti-Ro (SSA) antibodies. Renal involvement that required immunosuppressive therapy was present in 54% of the patients. Ninety percent of the patients tested positive for antinuclear antibodies, and 54% tested positive for anti-double-stranded DNA antibodies. Phenotyping of the fourth component of the complement was performed in 82% of the patients and showed a C4A4B2 phenotype, which is suggestive for the type I C2 deficiency. CONCLUSIONS: Most patients with lupus erythematosus associated with C2 type I deficiency are photosensitive, and this is probably related to the presence of anti-Ro (SSA) autoantibodies. The prognosis for those patients is not better than that for patients with lupus erythematosus in general.

Adolescent↗
PubMed2000

Analysis of solid-supported oligonucleotides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

This study presents matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) as a powerful tool to analyze and characterize oligonucleotides covalently linked to a solid support during their synthesis. The analysis of the fragment ions generated either in negative or positive mode allows direct and easy access to the nucleotide sequence and identification of the internucleosidic linkage. The mechanisms of the fragmentation of the solid-supported oligonucleotides induced by MALDI-TOFMS are discussed. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2000

Relationship between quadriceps strength and rate of loading during gait in women.

One function of skeletal muscle is to serve as the body's shock absorbers and thus dampen rates of loading during activity. The aim of this cross-sectional study was to determine the significance of muscle strength on rates of loading during gait. Thirty-seven women (mean age: 34.5 +/- 8.2 years) were solicited by advertisement and placed into one of two groups-strength-trained or sedentary-on the basis of training history. They walked (10 trials) over a 10-m walkway at a controlled speed of 1.22-1.35 m/s while the rate of loading was sampled with a 1,000-Hz force platform. Quadriceps and hamstring strength was measured at 90 degrees/s with an isokinetic dynamometer. Statistical analyses (p < 0.05) included descriptive statistics and unpaired t tests for comparison between groups. The women in the sedentary group weighed more and had significantly less concentric and eccentric strength of the quadriceps and hamstrings relative to body weight than did those in the strength-trained group. In addition, they demonstrated significantly higher rates of loading (2.21 +/- 0.15 compared with 1.75 +/- 0.08%wt/ms) than those in the strength-trained group.

Adult↗
PubMed2000

Molecular phylogeny of European muroid rodents based on complete cytochrome b sequences.

Phylogenetic relationships among 18 species of mainly European muroid rodents that belong to three subfamilies were estimated using complete sequences of the mitochondrial cytochrome b gene. The inferred monophyly of the subfamilies Murinae (mice and rats) and Arvicolinae (voles, lemmings, and muskrats) is in agreement with previous studies. Within the Murinae, the morphology-based division of the genus Apodemus into three subgenera is supported by these DNA sequence data. The relationships among the different genera of the Murinae were generally poorly resolved, and the relationships of Micromys and Acomys to the other murine genera remained unresolved. Within the subfamily Arvicolinae, the relations of the genera Arvicola, Clethrionomys, and Microtus remained tentative with our data. However, within the Microtus group, there is a good molecular support for the phylogenetic relationships. These findings suggest that the origin of the different murine and arvicoline lineages was rapid, indicating an adaptive radiation with fast speciation.

Animals↗
PubMed2000

[Diagnosis of body dysmorphic disorder. A pilot study].

The assessment of body dysmorphic disorder (BDD) is complicated by poorly defined diagnostic criteria and a lack of valid instruments. The present pilot study examines the possible benefit of specific instruments in the discrimination of other body image disorders. Thirteen patients with BDD, 13 with disfiguring defects, and 21 with no significant impairment of appearance participated in the study. The participants were recruited from dermatological outpatients on the basis of semistructured diagnostic interviews and clinical ratings of disfigurement. Furthermore, structured interviews were conducted to determine comorbidity with depressive disorders and social phobia and to obtain a clinical rating of obsessive-compulsive symptoms using the modified version of the YBOCS for body dysmorphic disorders. In addition, the Beck depression inventory, the Social Phobia Scale, and the Social Interaction Anxiety Scale were completed. Patients with BDD differed significantly from disfigured and unimpaired patients in obsessive-compulsive symptoms, in particular obsessions, and the discrepancy between personal and clinical rating of disfigurement. However, depression and social phobia scores were only higher in comparison with unimpaired patients. Comorbidity with depressive disorders was significantly increased. Our results support the utility of the specific diagnostic instruments and indicate the particular importance of obsessive-compulsive symptoms in BDD.

Adult↗
PubMed2000

An updated and comprehensive rRNA phylogeny of (crown) eukaryotes based on rate-calibrated evolutionary distances.

Recent experience with molecular phylogeny has shown that all molecular markers have strengths and weaknesses. Nonetheless, despite several notable discrepancies with phylogenies obtained from protein data, the merits of the small subunit ribosomal RNA (SSU rRNA) as a molecular phylogenetic marker remain indisputable. Over the last 10 to 15 years a massive SSU rRNA database has been gathered, including more then 3000 complete sequences from eukaryotes. This creates a huge computational challenge, which is exacerbated by phenomena such as extensive rate variation among sites in the molecule. A few years ago, a fast phylogenetic method was developed that takes into account among-site rate variation in the estimation of evolutionary distances. This "substitution rate calibration" (SRC) method not only corrects for a major source of artifacts in phylogeny reconstruction but, because it is based on a distance approach, allows comprehensive trees including thousands of sequences to be constructed in a reasonable amount of time. In this study, a nucleotide variability map and a phylogenetic tree were constructed, using the SRC method, based on all available (January 2000) complete SSU rRNA sequences (2551) for species belonging to the so-called eukaryotic crown. The resulting phylogeny constitutes the most complete description of overall eukaryote diversity and relationships to date. Furthermore, branch lengths estimated with the SRC method better reflect the huge differences in evolutionary rates among and within eukaryotic lineages. The ribosomal RNA tree is compared with a recent protein phylogeny obtained from concatenated actin, alpha-tubulin, beta-tubulin, and elongation factor 1-alpha amino acid sequences. A consensus phylogeny of the eukaryotic crown based on currently available molecular data is discussed, as well as specific problems encountered in analyzing sequences when large differences in substitution rate are present, either between different sequences (rate variation among lineages) or between different positions within the same sequence (among-site rate variation).

Base Sequence↗
PubMed2000

The economic impact of smoking in Germany.

Smoking is a high-risk behaviour affecting health and economic welfare of society. Thus it is important to quantify the economic burden smoking places on social institutions in Germany. Approximately 33.4% of the male and 20.4% of the female population are current smokers. This study investigates the health care costs of smoking based on 1996 figures, focusing on the seven most frequent diseases associated with the inhalation of tobacco smoke: chronic obstructive pulmonary disease (COPD, international classification of diseases (ICD) 490-491); lung cancer (ICD 162); stroke (ICD 434-438); coronary artery disease (ICD 410-414); cancer of the mouth and larynx (ICD 140-149, 161) and artherosclerotic occlusive disease (ICD 440). A data search was carried out on MEDLINE, the German Institute for Medical Documentation and Information, and the Internet as well as in databases of health insurance companies and the German Federal institute of statistics. Direct and indirect costs were calculated separately. The results estimate the total smoking related health care costs (attributable fraction due to smoking) for COPD to be 5.471 billion EURO (73%), for lung cancer 2.593 billion EURO (89%), for cancer of the mouth and larynx 0.996 billion EURO (65%), for stroke 1.774 billion EURO (28%), for coronary artery disease 4.963 billion EURO (35%) and for atherosclerotic occlusive disease 0.761 billion EURO (28%). The economic burden of smoking related health care costs for Germany is 16.6 billion EURO. Smoking is therefore responsible for 47% of the overall costs of these diseases (35.2 billion EURO). In the view of the high costs for smoking, of which almost 50% are due to respiratory disease, pneumologists should enhance their effort in primary, secondary and tertiary prevention.

Arteriosclerosis↗
PubMed2000

M-type K+ currents in rat cultured thoracolumbar sympathetic neurones and their role in uracil nucleotide-evoked noradrenaline release.

Cultured sympathetic neurones are depolarized and release noradrenaline in response to extracellular ATP, UDP and UTP. We examined the possibility that, in neurones cultured from rat thoracolumbar sympathetic ganglia, inhibition of the M-type potassium current might underlie the effects of UDP and UTP. Reverse transcriptase-polymerase chain reaction indicated that the cultured cells contained mRNA for P2Y(2)-, P2Y(4)- and P2Y(6)-receptors as well as for the KCNQ2- and KCNQ3-subunits which have been suggested to assemble into M-channels. In cultures of neurones taken from newborn as well as from 10 day-old rats, oxotremorine, the M-channel blocker Ba(2+) and UDP all released previously stored [(3)H]-noradrenaline. The neurones possessed M-currents, the kinetic properties of which were similar in neurones from newborn and 9 - 12 day-old rats. UDP, UTP and ATP had no effect on M-currents in neurones prepared from newborn rats. Oxotremorine and Ba(2+) substantially inhibited the current. ATP also had no effect on the M-current in neurones prepared from 9 - 12 day-old rats. Oxotremorine and Ba(2+) again caused marked inhibition. In contrast to cultures from newborn animals, UDP and UTP attenuated the M-current in neurones from 9 - 12 day-old rats; however, the maximal inhibition was less than 30%. The results indicate that inhibition of the M-current is not involved in uracil nucleotide-induced transmitter release from rat cultured sympathetic neurones during early development. M-current inhibition may contribute to release at later stages, but only to a minor extent. The mechanism leading to noradrenaline release by UDP and UTP remains unknown.

Adenosine Triphosphate↗
PubMed2000

Electrically evoked release of [(3)H]noradrenaline from mouse cultured sympathetic neurons: release-modulating heteroreceptors.

Cultured neurons from the thoracolumbar sympathetic chain of newborn mice are known to possess release-inhibiting alpha(2)-autoreceptors. The present study was carried out in a search for release-modulating heteroreceptors on these neurons. Primary cultures were preincubated with [(3)H]noradrenaline and then superfused and stimulated by single pulses, trains of 8 pulses at 100 Hz, or trains of 36 pulses at 3 Hz. The cholinergic agonist carbachol reduced the evoked overflow of tritium. Experiments with antagonists indicated that the inhibition was mediated by M(2) muscarinic receptors. The cannabinoid agonist WIN 55,212-2 reduced the evoked overflow of tritium through CB(1) receptors. Prostaglandin E(2), sulprostone, and somatostatin also caused presynaptic inhibition. The inhibitory effects of carbachol, WIN 55,212-2, prostaglandin E(2), and somatostatin were abolished (at the highest concentration of WIN 55, 212-2 almost abolished) by pretreatment of the cultures with pertussis toxin (250 ng/ml). Several drugs, including the beta(2)-adrenoceptor agonist salbutamol, opioid receptor agonists, neuropeptide Y, angiotensin II, and bradykinin, failed to change the evoked overflow of tritium. These results demonstrate a distinct pattern of presynaptic inhibitory heteroreceptors, all coupled to pertussis toxin-sensitive G proteins. The lack of operation of several presynaptic receptors known to exist in adult mice in situ may be due to the age of the (newborn) donor animals or to the culture conditions.

Action Potentials↗
PubMed2000

Mitochondrial evidence on the phylogenetic position of caecilians (Amphibia: Gymnophiona).

The complete nucleotide sequence (17,005 bp) of the mitochondrial genome of the caecilian Typhlonectes natans (Gymnophiona, Amphibia) was determined. This molecule is characterized by two distinctive genomic features: there are seven large 109-bp tandem repeats in the control region, and the sequence for the putative origin of replication of the L strand can potentially fold into two alternative secondary structures (one including part of the tRNA(Cys)). The new sequence data were used to assess the phylogenetic position of caecilians and to gain insights into the origin of living amphibians (frogs, salamanders, and caecilians). Phylogenetic analyses of two data sets-one combining protein-coding genes and the other combining tRNA genes-strongly supported a caecilian + frog clade and, hence, monophyly of modern amphibians. These two data sets could not further resolve relationships among the coelacanth, lungfishes, and tetrapods, but strongly supported diapsid affinities of turtles. Phylogenetic relationships among a larger set of species of frogs, salamanders, and caecilians were estimated with a mitochondrial rRNA data set. Maximum parsimony analysis of this latter data set also recovered monophyly of living amphibians and favored a frog + salamander (Batrachia) relationship. However, bootstrap support was only moderate at these nodes. This is likely due to an extensive among-site rate heterogeneity in the rRNA data set and the narrow window of time in which the three main groups of living amphibians were originated.

Animals↗
PubMed2000

Hysteroscopic surgery--complications and their prevention.

During the last few years, diagnostic hysteroscopy has become a standard procedure in the diagnosis of abnormal uterine bleeding, sonographically suspicious endometrial reflex and fertility disorders. At the same time the hysteroscopic treatment of intrauterine pathology is becoming more common. Today, hysteroscopic resection of uterine myomas, dissection of uterine septa, and endometrial ablation are standard procedures. Using monopolar cutting devices and saline-free distension media, hysteroscopic surgery bears specific risks. The knowledge of these risks is important to avoid typical complications of operative hysteroscopy. This article gives an overview about the most common procedures of operative hysteroscopy and the combined risks. Criteria for a safe procedure are defined in order to increase the quality management of operative hysteroscopy.

Endometrium↗
PubMed2000

The 'HysteroTrainer'--an in vitro simulator for hysteroscopy and falloposcopy. Experimental and clinical background and technical realisation including the development of organ modules for electrothermal treatment.

Hysteroscopy and falloposcopy are routine procedures in gynecological endoscopy. Injuries to the cervix or uterine perforations due to blind manipulation or wrong use of instruments are the most common complications associated with these procedures. In vitro simulators have been shown to be valuable tools in the laparoscopic training of physicians. Therefore we developed a simulator for hysteroscopy offering realistic anatomical and physiological training conditions. Additionally, we examined different polymer substances as basic materials for organ modules that allow the realistic application of electric instruments, e.g. resector blades and rollerball.

Equipment and Supplies↗
PubMed2000

Cholinesterase activities determination in frozen blood samples: an improvement to the occupational monitoring in developing countries.

1. Studies were carried out on rural workers in Brazil to determine the decrease in the activity of plasma butyrylcholinesterase (BChE), erythrocyte cholinesterase (AChE) associated with exposure to organophosphorus pesticides (OP). The goal of this work is to help prevent injury to these workers. 2. In developing countries the distance between area of pesticide use and reference laboratories is a drawback for analytical techniques, since cholinesterase activity determinations require fresh blood samples. Field methodologies can be a useful alternative to laboratory tests, however they are not as sensitive as those found in laboratories. 3. The modification of Ellman's Method presented in this paper allows blood samples to be frozen and maintain enzymatic stability: 7 days for AChE and 3 days for BChE. The proposed method is also more sensitive than Ellman's Method Modified by Magnotti (EMMM). 4. The results suggest that the Ellman Method Modified by Oliveira-Silva (EMMOS) is valid for monitoring procedures. This method represents an important contribution to the process of monitoring OP exposures, since the evaluations no longer have to be conducted near the site of OP use.

Acetylcholinesterase↗