Changes of pressure and humidity affect olfactory function

The present study aimed at investigating the question whether olfactory function changes in relation to barometric pressure and humidity. Using climate chambers, odor threshold and discrimination for butanol were tested in 75 healthy volunteers under hypobaric and hyperbaric, and different humidity conditions. Among other effects, olfactory sensitivity at threshold level, but not suprathreshold odor discrimination, was impaired in a hypobaric compared to a hyperbaric milieu, and thresholds were lower in humid, compared to relatively dry conditions. In conclusion, environmental conditions modulate the sense of smell, and may, consecutively, influence results from olfactory tests.     

Experimentally induced nasal irritation

The aim of this study was to develop a method that is suited for the induction of nasal irritation. For this purpose inflammatory responses were analysed after challenging the nasal mucosa with experimentally induced cold, dry air (8 l/min, 22 degrees C, 20 %RH). To assess inflammatory effects we determined inflammatory mediators (prostaglandin E2 [PGE2], thromboxane B2 TXB2[, peptide leukotrienes pLT: LTC4, LTD4, LTE4[) in nasal lavage fluid which was sampled before, immediately after suprathreshold stimulation, and one hour after termination of the stimulation. In addition, subjects estimated the intensity of pain during the stimulation. Cold, dry air produced strong painful sensations which increased throughout the stimulation period. A significant increase of the inflammatory mediator pLT was observed after stimulation; mean concentrations of PGE2 and TXB2 also showed a tendency to increase. One hour after termination of the stimulation the concentration of these inflammatory mediators returned to baseline which indicates the reversibility of the effects of nasal irritation. These data suggest, that this model may be a useful tool in investigations of mucosal irritation as, for example, induced by environmental agents.     

'Identical' twins with discordant karyotypes

A chromosomal abnormality in one of the fetuses of a monozygotic twin pregnancy is a rare phenomenon. In the prenatal unit of our cytogenetics laboratory we have recently come across two such heterokaryotypic twin pregnancies. In both cases ultrasound abnormalities were detected in one fetus of each twin pair. Chromosomal analysis showed that one twin pregnancy was discordant for trisomy 21 and the other for 45,X. Ultrasonographic examination suggested a monochorionic twin pregnancy in each case and DNA studies confirmed that both sets of twins were monozygotic. Both pregnancies were terminated. Biopsies taken from different sites of the placentas showed chromosomal mosaicism in both cases. There was no clear correlation between the karyotype found close to the site of the umbilical cord insertion in the placenta and the karyotype of the fetus. Sampling of amniotic fluid from both sacs is recommended in diamniotic twin pregnancies if one (or both) of the fetuses has ultrasound abnormalities, even if the twins are apparently monochorionic.     

Effects of azapropazone on pain-related brain activity in human subjects.

1. The dose-related effects of azapropazone on (i) event-related and spontaneous EEG-activity and (ii) the subjects' pain ratings were investigated using an experimental human pain model based on both chemo-somatosensory event-related potentials (CSSERP) and subjects' pain ratings. 2. Healthy subjects (n = 20) participated in a placebo-controlled, randomized, double-blind, four-way cross-over study. Single doses of azapropazone (300 mg, 600 mg and 1200 mg) and placebo were administered intravenously. Each experiment consisted of five sessions (before and 1, 2, 4 and 8 h after administration of the medication). Each session lasted for approximately 40 min. In the first 20 min, pain was induced by short CO2-stimuli presented to the right nostril (phasic pain; interstimulus interval 30 s) and EEG was recorded from five positions. CSSERPs were obtained in response to painful CO2-stimuli. In the following 20 min period, tonic pain was induced by a constant stream of dry air introduced in the left nostril. Subjects rated the intensity of both phasic and tonic pain by means of a visual analogue scale. Additionally, a frequency analysis of the spontaneous EEG was performed. 3. Azapropazone reduced the pain-related CSSERP-amplitudes at frontal and parietal recording positions. This topographical pattern was observed in previous studies with opioids, while NSAIDs such as flurbiprofen and ketoprofen exerted effects at frontal and central positions. In contrast to other NSAIDs, administration of azapropazone resulted in a reduction of the frequency bands alpha 1, delta and theta of the spontaneous EEG. At the subjective level, analgesic effects of azapropazone were observed in the ratings of tonic pain. 4. Analgesic properties of azapropazone were demonstrated in man. The topographical pattern of the changes in the CSSERPs and the effects on EEG background activity suggest a central component of the analgesic action of azapropazone.     

Heart transplantation--indications and results]

Heart transplantation has become a standard procedure in the treatment for irreversible heart failure. Criteria for both recipients and donors have been extended. One year survival now reaches 81%. In the immediate postoperative course patients are endangered by infection. In the long-term course coronary artery disease of the transplanted heart becomes the most serious problem. Alteration of liver and kidney function due to chronic medication as well as malignancies and hypertension also occur. In case of chronic transplant failure retransplantation may be indicated. Acute cardiac failure before transplantation nowerdays can be treated by mechanical circulatory assist devices.     

Feldionen- und Elektronenstoß-Massenspektrometrie von Polymeren und Copolymeren, 3. Copolymere des α-Methylstyrols mit Methylmethacrylat und Acrylnitril

Pyro-field ion mass spectrometry was used to study the primary fragments as well as the depolymerization behaviour of some α-methylstyrene (α-MS) copolymers. α-MS-methyl methacrylate (MMA) copolymers, when pyrolyzed, decompose mainly into the two monomers. The zip-depolymerization usually proceeds through the whole chain, disregarding the hetero-links between different monomeric units. Hetero-fragments are formed only with a small probability; still lower is the concentration of homo-dimers in the pyrolysate. Primary fragments of poly(acrylonitrile) (PAN) are acrylonitrile (AN), (AN)₂, (AN)₃, HCN, C₃H₅CN, C₄H₇CN, C₅H₉CN and higher nitriles. During pyrolysis of α-MS-AN copolymers, α-MS sequences zipdepolymerize with formation of the monomer. This retropolymerization stops at heterolinks, and fragments of the type α-MS-AN or α-MS-(AN)₂ are formed. Long AN sequences in the copolymer cause, as PAN itself, formation of AN oligomeres as well as higher alkene cyanides. Isolated AN units lead to the formation of monomeric AN.     

Copolymere aus Vinylhalogeniden und olefinen. II. Quantitative IR-spektroskopische untersuchungen an Vinylchlorid/Isobuten-Copolymeren

To identify sequence-sensitive bands in the IR-spectra of vinylchloride/isobutene-copolymers, the superimposed δ(CH₂) and δ(CH₃), ρ(CH₂) and ν(CCl) vibrations between 1500 and 1350 cm^?1, 1000 and 850 cm^?1, and 730 and 600 cm^?1 respectively were separated into individual bands. The half band widths and the relative integral absorbances of these bands were determined in dependence of the composition of a copolymer series with a polymerisation temperature of +23°C.