79. Intramyokardialer pH-Wert als Indicator für die Wiederbelebbarkeit des künstlich stillgestellten Herzens

Zusammenfassung Bei tierexperimentellen Untersuchungen mit kardioplegischem Herzstillstand bei 35° C und 15° C in Halothan- und Dipidolornarkose und bei Experimenten mit rein ischämischem, normothermem Herzstillstand in Halothan-, Dipidolor-, Barbiturat-, Chloroform-, Penthrane- und Ketaminenarkose wurde parallel zur Bestimmung der Myokardkonzentration an energiereichen Phosphaten und Milchsäure der intramyokardiale pH-Wert gemessen. Dabei sollte geprüft werden, ob der intramyokardiale pH-Wert als Indicator für die Ischämietoleranzzeit während eines künstlichen Herzstillstandes verwendet werden kann. In allen Versuchsgruppen sinkt der pH-Wert während der Ischämie ab. In den Kardioplegieversuchen bei 35° C und 15° C wurde bei Erreichen der die sogenannte praktische Grenze der Wiederbelebungszeit (t-ATP) kennzeichnenden ATP-Konzentration von 4 mol/g ein pH-Wert von 6,17 (±0,03) gemessen. Dieser Wert wurde bei 35° C nach 45 min, bei 15° C nach 260 min erreicht. Bei normothermer Ischämie betrug der mittlere pH-Wert beit-ATP 6,31 (±0,03). Die ATP-Zeiten lagen zwischen 17 min in der Halothangruppe und 5 min bei den Ketaminversuchen.

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Intramyocardial pH as indicator for the resuscitability of the heart during artificial cardiac arrest

Summary The goal of this work was to determine whether intramyocardial pH can predict the resuscitability of the artificially arrested heart. Under Halothane. and Dipidolor-anaesthesia the experiments in dogs were made with cardioplegic cardiac arrest at a temperature of 35° C and 15° C. In other experiments ischemic cardiac arrest was used under different anaesthetics: Halothane, Dipidolor, Barbiturate, Chloroform, Penthrane and Ketamine. In both groups intramyocardial pH, the myocardial concentration of highenergy-phosphates (PKr and ATP) and lactic acid was analysed simultanously. The fall of myocardial ATP to 4 moles/g determines the end of the tolerable occlusion time, the so called survival time (t-ATP). At this point, the ischaemic heart is just able to recover without a prolonged recovery period. In all experiments, there is also a decline of intramyocardial pH during ischemia. In cardioplegic cardiac arrest the mean pH 6.17 (±0.03) accords to a fall of the ATP-content to 4 moles/g. This value was reached at 35° C after 45 min, at 15° C after 260 min. In ischemic cardiac arrest the corresponding pH mean value was 6.31 (±0.03) reached in a range from 17 min (Halothanegroup) to 5 min (Ketamine-group).

     

New and unusual O alleles at the ABO locus are implicated in unexpected blood group phenotypes

BACKGROUND: In the ABO blood group system mutations in the A gene may lead to weak A subgroups owing to a dysfunctional 3-alpha-N-acetylgalactosaminyltransferase. STUDY DESIGN AND METHODS: Blood and DNA were investigated to correlate weak A phenotypes with genotype, and an overrepresentation of the infrequent O2 allele was observed. Consequently, 57 available O2 alleles were examined in detail. RESULTS: Two new O2 alleles were identified having mutations resulting in Gly229Asp with or without Arg217Cys. A recently described O2 variant (488C>T; Thr163Met) was also found. Surprisingly, both the original and the variant O2 alleles were associated with either O or Aweak phenotypes. Three novel O alleles surfaced in six other samples with suspected A subgroups. These were A1-like alleles having nonsense mutations causing premature truncation at codons 56, 107, or 181. A second example of the rare O3 allele was also identified. A newly described O1 allele having 768C>A was found to be the third most frequent O allele among Swedish donors. Of the five novel O alleles, three were incorrectly interpreted as A1 following routine ABO genotyping. CONCLUSION: Apparent O alleles lacking 261delG may cause weak A expression on red blood cells and/or inhibit anti-A production. A hypothesis that exchange of genetic material between principally dissimilar O alleles during mitosis ("autologous chimerism") restores glycosyltransferase activity in some cells would explain this interesting phenomenon.     

Novel glycolipid variations revealed by monoclonal antibody immunochemical analysis of weak ABO subgroups of A

BACKGROUND AND OBJECTIVES: The chemical basis of the subgroups of A is largely unknown. We used thin-layer chromatography immunochemical staining techniques together with a range of characterized monoclonal reagents to analyse glycolipids isolated from a variety of weak subgroups. MATERIALS AND METHODS: Glycolipids isolated from red cells collected from nine genetically defined individuals of the rare subgroups of A, including a novel A(3) allele (A(2) 539G>A) not described previously, were subjected to a highly sensitive thin-layer chromatographic immunochemical analysis. RESULTS: Semicharacterized monoclonal antibodies revealed that, in addition to the expected quantitative differences between common phenotypes and the weak subgroups, qualitative glycolipid differences (or at least an apparent qualitative basis), caused by major changes in the ratios of different structures exist. Specifically it was found that the weakest A-expressing samples (A(el) phenotype) appeared to express an unusual A structure in the 8-12 sugar region. Variable expression of several structures in one of the A weak samples were suggestive of novel blood group A structures. CONCLUSIONS: Although no structural characterization could be undertaken, the results are clearly indicative that the variant glycosyltransferases of the rare ABO subgroups are not only inefficient, but they may potentially synthesize novel ABO structures.     

Low-dose aspirin in a short regimen as standard treatment in in vitro fertilization: a randomized, prospective study

OBJECTIVE: To determine if treatment with low-dose aspirin in a short regimen improves the outcome in a nonselected IVF population as compared with no treatment. DESIGN: Prospective, randomized study where IVF patients were given aspirin or received no treatment. SETTING: IVF clinic. PATIENT(S): The study included 1380 consecutive IVF cycles. INTERVENTION(S): Women undergoing IVF were randomly assigned to treatment with aspirin 75 mg daily from the day of embryo transfer (ET) until pregnancy test or no treatment in an open study. MAIN OUTCOME MEASURE(S): Birth rate per ET. RESULT(S): Background characteristics were similar in the two groups studied except for a minor difference in number of embryos transferred (2.1 vs. 2.0). Birth rate was 27.2% in the aspirin group as compared with 23.2% in the nontreated group, giving an odds ratio, adjusted for number of embryos transferred, of 1.2 (95% confidence interval, 1.0-1.6). CONCLUSION(S): The increased birth rate with aspirin compared with no treatment was significant. Given the importance of every birth in IVF, especially when taking into account the limited number of IVF cycles that are normally performed in an individual woman, any treatment to improve birth rate is important.     

Regional block and DVT prophylaxis

The last few years have seen increasing concerns among anaesthetistsabout the risks of pharmacological prophylaxis for thromboembolicdisease. Increased bleeding during or after surgery is one concern,but of greater significance is the possibility of an increasedpredisposition to haematoma formation when regional block isused. Most of the recent consideration of this problem has beenin relation to vertebral canal haematoma formation after centralnerve block. Some thought must be given also to the possibilityof haematoma formation after peripheral techniques when thetarget nerve is deeply placed so that pressure cannot be usedto control bleeding after needle insertion. However, this reviewwill be focused on vertebral canal haematoma.     

Developmental profiles and auditory perception in 25 children attending special preschools for language-impaired children

AIM: To study different developmental profiles and auditory perception in a representative group of children with language impairment (LI). METHODS: A multidisciplinary investigation was carried out in a group of 25 children attending units specifically for language-impaired children. An assessment of the cognitive level, motor performance, behaviour and auditory perception was performed and the results were compared with those for age-matched groups of children. RESULTS: Among those with moderate or severe language impairment (LI), around 90% had additional developmental disorders. In three tests of auditory perception, children with LI had problems with working memory and speech discrimination. No problems were found with the children's temporal resolution in auditory perception. Another conclusion from the auditory perceptual tests was that the children's cognitive abilities were important for their success in these tests. CONCLUSION: Neurodevelopmental deviations are very common in LI children. The optimal route for the assessment and treatment of these children would be a multidisciplinary approach.