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Biomedical subjects

G Weiler

Publications and source records attributed to G Weiler.

At least 19 recordsLinked to original sources
PubMed2005

Post-mortem evaluation of 415 pacemakers: in situ measurements and bench tests.

AIM: The hypothesis was that there is more undetected dysfunction of implanted pacemaker systems than that detected and corrected. This prompted a research project (sponsored by the German Research Foundation) to detect pacemaker abnormalities and evaluate their complications for patients, thus, proving or disproving the hypothesis. METHODS AND RESULTS: Four hundred and fifteen pacemakers of deceased patients were analyzed assessing their functionality by in situ measurements and bench tests including five measurements and one telemetric interrogation. Results were divided into four categories and statistically evaluated. Life-threatening abnormalities were found in 3.8%, potentially life-threatening in 3.7%, probably symptomatic, divided into atrial and ventricular problems, 13.3% and 2.8%, respectively, and premature exhaustion in 1.2%. Three of 179 bipolar ventricular leads and 2 of 131 bipolar atrial leads had insulation defects corresponding to 1.7% and 1.5%, respectively. The bipolar complication rate was 2.8 times higher than unipolar. CONCLUSION: The pacemaker patients investigated, living 4 years with their pacemaker on average, had a post-mortem evaluated complication rate of the category "life-threatening" of 3.8%. This result corresponds to an annual complication rate of 0.94% compared with a rate of only 0.39% in an earlier investigation.

Aged↗
PubMed2004

[Risks of drug screening using immunoassays].

Now-a-days immunoassays are world wide used for the rapid screening of drugs. Despite the fact that they are a highly valuable tool for the test of legal and illicit drugs, there is a non-negligible risk of false positive and false negative findings and many pitfalls must be taken into account when using these tests in an uncritical manner and without valid confirmation procedures.

Cross Reactions↗
PubMed2002

An unusual airplane crash--deadly life saver. Unintentional activation of an automated reserve opening device causing airplane accident.

A Pilatus PC 6 "Turbo-Porter" crashed after having dropped skydivers. The interdisciplinary investigation of the crash revealed that the automated reserve opening device "Student-CYPRES" which the passenger wore on his parachute system had been set off during the landing approach. The parachute pulled the passenger out of the airplane. Subsequently the parachute got caught at the horizontal tail, and its wearer was instantly killed by internal decapitation. The airplane crashed because of its damaged horizontal tail, and the pilot lost his life.

Accidents, Aviation↗
PubMed2002

Universal approach to pharmacokinetic monitoring of immunosuppressive agents in children.

Current data indicate that pharmacokinetic (PK) monitoring of cyclosporin microemulsion (CsA) should be performed using the 2-h concentration (C2), that tacrolimus (Tac) is commonly monitored using the trough level, and mycophenolate mofetil (MMF) should be monitored using the 1-h (C1), 2-h (C2) and 6-h (C6) concentrations. The three differing time-point requirements are cumbersome, and we aimed to develop universal guidelines for all three drugs using a large number of full PK profiles in children. One-hundred and twenty two stable pediatric patients, receiving either CsA (165 PK profiles, 69 patients, 24 with concomitant MMF) or Tac (122 PK profiles, 53 patients, 18 with MMF) were analyzed retrospectively. Pearson r for the CsA C2 was 0.90 [95% confidence interval(CI): 0.86-0.92], for Tac C2 r was 0.86 (95% CI: 0.80-0.90), and for MPA C2 r was 0.77 (95% CI: 0.68-0.83), respectively. For MPA, at least three time-points are required to accurately estimate the area under the concentration-time curve (AUC), and C1, C2 and C6 serve as best markers. Excellent AUC estimations could be obtained from a limited sampling strategy from C1, C2 and C6 or C0, C1, C2 and C4 with clinically acceptable errors for all three drugs. The AUC can be estimated with great precision by using an identical approach for all three drugs. Target AUCs for a given time-point after transplantation remain to be established.

Adolescent↗
PubMed2001

Multiple homicides as a result of chloroform poisoning: case report and experimental study.

Two cases (involving five murder victims) of multiple homicide by inhalational chloroform intoxication are reported. In the discussion of the findings the valence of toxicological analyses is underlined with regard to the possibility of forcible external suffocation due to occlusion of the respiratory orifices by means of a chloroform-soaked soft covering. In addition storage experiments were performed at +4, +20 and -20 degrees C with cadaver blood mixed with chloroform. The optimal solution for avoiding volatile losses was stored in glass tubes with ground glass stoppers. In cases of unclear death in which involvement of volatile substances is suspected it is, therefore, advisable to preserve an additional blood sample at -20 degrees C in glass tubes that are only opened for the analysis of volatile substances.

Adolescent↗
PubMed2001

Traumatic venous aneurysm of the popliteal vein with outcome: a case report and review of the literature.

A case of sudden death due to recurrent pulmonary thromboembolism is described. The fatality took place three and a half weeks following blunt trauma to the left popliteal region. The patient died unexpectedly. Autopsy revealed the source of the emboli as a sacciform venous aneurysm of the popliteal vein, an entity seldom described, but important to consider in cases of soft tissue popliteal masses or unexplained pulmonary embolism, especially in otherwise healthy individuals.

Adult↗
PubMed2000

Errors in ABO typing of blood stains using PCR.

Genotypes of the ABO blood group system were investigated using a multiplex PCR and subsequent restriction enzyme digestion on experimental blood stains. Differences were found when typing blood between the PCR and serological methods and one blood sample, typed as B with the agglutination test was classified as AB using the method described here. The subsequent sequencing procedure revealed the genotype to be BB. Methodological causes for errors in typing which should be taken into consideration are discussed.

ABO Blood-Group System↗
PubMed1998

High ethanol tolerance in young adults is associated with the low-activity variant of the promoter of the human serotonin transporter gene.

Central serotonergic neurotransmission has been implicated in the aetiology of ethanol tolerance and dependence. Cellular expression of the serotonin transporter and serotonin reuptake is modulated via a polymorphic, repetitive element in the 5'-flanking regulatory region of the serotonin transporter gene (5-HTTLPR). We report the association of the low-activity, short variant of the 5-HTTLPR with high ethanol tolerance among young adults in a case-control association study (n = 713). The low-activity 5-HTTLPR showed a significantly increased allele frequency (chi2 = 7.30; df = 2; P = 0.007) and genotype frequency among young adults (< or =26 years) with high ethanol tolerance homozygous for the short allele (chi2 = 7.58; df = 1; P = 0.02). The estimated odds ratio for the homozygous short variant compared to the homozygous long variant was 2.82 (95% CI 1.30-6.11). This indicates that the low-activity 5-HTTLPR may be involved in the neuronal mechanisms responsible for ethanol tolerance and dependence.

Adult↗
PubMed1997

Histomorphologic studies of the glottic region to elucidate the pathogenesis and functional significance of fibrinoid vocal cord lesions in infants and young children.

Focal lesions of the vocal cord in form of fibrinoid necrosis and thickening of the basement membrane are morphological findings in infants and young children that receive only scant attention and are also controversially valued. We discuss two causes for the pathogenesis of these findings: (1) recurrent laryngospasms and (2) a laryngeal phonotrauma resulting from frequent spells of shrill, presumably high-frequency crying. The aim of our study therefore was to gain insight into the development and functional significance of these lesions by examining their histological patterns and to draw the pertinent conclusions. In 56 deaths (natural and unnatural causes, fetal life up to 4 years, no pathological or traumatic laryngeal lesions) histological investigations were carried out on putrefaction-free material. For the histomorphological studies, horizontal sections through the region of the vocal cord were obtained and stained according to conventional and immunohistochemical staining methods. In 42 cases the thickness of the basement membrane was determined morphometrically. In 12 of the 56 cases (21%) we observed staged variations of focal lesions, ranging from fibrinoid necrosis to degenerative lesions with pronounced macrophage involvement and deposits of PAS-positive plaques. Measurements at the basement membrane revealed a thickness of 7.9 microm. Separate measurements at the anterior and posterior portions of the vocal fold showed a ratio of 1.7:1. When the cases were subdivided into those with and without fibrinoid necrosis the ratios were 2.5:1 and 1.5:1. This different pattern makes it unlikely that laryngospasm is the sole or essential cause. Pathogenetically more important might be phonatory overstraining due to maximum vibrations in only the anterior portions of the vocal fold, which is not specific for later SIDS victims. This assumption is also supported by the often observed conspicuous phonetic behavior of some later SIDS victims and the absence of these stage-like vocal cord lesions in stillborns and adults. It is presumably an age-specific, temporary finding which is completely reversible.

Basement Membrane↗
PubMed1997

Additional primer sets for an amelogenin gene PCR-based DNA-sex test.

When aligning the human amelogenin X (AmelX)-gene with the human amelogenin Y (AmelY)-gene, 19 regions of absolute homology ranging in size from 22 to 80 bp, 5 deletions located on AmelX from 1 to 6 bp and 5 deletions 1-183 bp long located on AmelY can be observed. The regions of absolute homology are used to design primer sets which span deletions of the X- and/or Y-chromosome. The PCR products generated on the X- and Y-homologues differ in size. New regions of deletions and newly designed primers are described to facilitate the integration of the amelogenin sex test into multiplex PCR reactions.

Amelogenin↗
PubMed1994

Horizontal polyacrylamide gel electrophoresis for the separation of DNA fragments.

A discontinuous borate/formate buffer system is presented for horizontal polyacrylamide gel electrophoresis of DNA fragments. The resolution potential of the system could be altered by changing the total monomer concentration (5-9%T), the concentration of the crosslinker piperazine diacrylamide (2-5%CPDA), as well as the concentration of formate in the gel (40-120 mM), the leading ion of the buffer system. The separation of DNA fragments would be improved by increasing the migration distance from 22 to 28 cm. This discontinuous polyacrylamide gel electrophoresis system proved highly reproducible.

Buffers↗
PubMed1994

Screening, identification and determination of the two new hypnotics zolpidem and zopiclone.

This article reports basic analytical data for screening and detection of the hypnotics zolpidem (CAS 82626-48-0) and zopiclone (CAS 43200-80-2) by using corrected hR-values, GC (gas chromatography) retention indices, UV solvent spectra and remission spectra. Beside this a HPTLC (high-performance thin-layer chromatography)-procedure for quantification is described.

Azabicyclo Compounds↗
PubMed1993

[Determination of limit values for "safe driving" in street traffic with reference to centrally active drugs from the pharmacokinetic and pharmacodynamic viewpoint].

When establishing threshold values for "driving under the influence of centrally acting compounds" it must be considered that many parameters have an important influence on the pharmacokinetic properties (e.g. volume of distribution, the elimination half-life, and the drug concentration in body fluids) and the pharmacodynamic action (e.g. impairment of skills related to driving). This article describes these inter-and intraindividual parameters from the pharmacokinetic (influence of body weight, age, gender, genetics, diseases, other compounds as ethanol and antacids, enzyme induction, enzyme inhibition, first-pass effects, pharmacokinetic interaction, chronopharmacokinetics, mode of application) and pharmacodynamic (tolerance, pharmacodynamic interaction, pharmacogenetic, chronopharmacodynamic, pathological alterations) point of view. The large variabilities clearly indicate, that preliminary threshold values should be chosen high enough to prevent prejudice of traffic participants. A "consensus value" could be established and continuously monitored by a commission. Beside this the high relevance of valid analytical investigations must be regarded.

Adult↗
PubMed1993

["Iatrogenic" fatal gas gangrene infection].

The problems associated with lethal gas gangrene infections that arise in connection with medical treatment are described and discussed, based on our own observations and on cases reported in the literature. Special emphasis is placed on questions relating to causality and responsibility. The difficulties encountered in the evaluation of such "iatrogenic" gas gangrene infections are due to the fact that clostridia occur ubiquitously, i.e. that they also reside in the human organism, for instance on the skin. For this reason a positive bacteriological diagnosis of gas gangrene does not necessarily mean that a clinically relevant infection and/or disease state is present at the same time. The implications for morphological practice arising from this situation are discussed, especially with regard to the significance of the intravital, agonal or postmortem bacteriological diagnosis of gas gangrene. Questions concerning the obligation to report such cases when encountered during forensic autopsies are also addressed.

Adult↗
PubMed1992

[Experiences with congener analysis of beverages without congeners].

Many alcoholic beverages contain no forensically relevant concentrations of congeners. Despite this fact they can be subject of a congener analysis. Another applicability of congener analyses are cases in connection with a differentiation between the short- or longterm ingestion of beverages containing 1-propanol and iso-butanol as congeners (e.g. beer or wine).

1-Propanol↗
PubMed1991

[Amylase 2 phenotypes in Central Hessia and value in paternity assessment].

In 677 unrelated persons from the Central Hessian region, the following distribution of amylase 2 phenotypes was found: type 1 in 89.22%, type 2-1 in 8.57%, type 2 in 0.30%. The special bands 3 and 4 could be detected in 0.59% and the new bands F1-6 (on the anodal side of the 1 band) we have described could be demonstrated in 1.33%. In 244 cases, paternity could be excluded on the basis of amylase 2 in seven cases (i.e. 2.9%); this was a classic exclusion in six cases. In the biostatistical calculation of the probability of paternity, this enzyme system provides probabilities which justify routine determination of amylase 2.

Adult↗