Relationship between severity of nocturnal desaturation and adaptive thermogenesis: preliminary data of apneic patients tested in a whole-body indirect calorimetry chamber.

The purpose of this study was to investigate the possibility of a relationship between the severity of obstructive sleep apnea syndrome (OSAS) and adaptive thermogenesis. Daily energy expenditure (DEE) and sleeping metabolic rate (SMR) were measured in apneic and a priori nonapneic subjects who were tested in a whole-body indirect calorimetry chamber for 24 h. The apneic patients were diagnosed by nocturnal home oximetry to determine the percentage of total recording time spent below 90% arterial oxygen saturation (% TRT <90% SaO(2)). Reference equations established from body weight and age in nonapneic subjects were used to predict DEE and SMR in apneic patients. The predicted values of the apneic patients were then compared to their measured values. No significant difference was found between predicted and measured values in SMR nor in DEE. We observed a significant relationship between the severity of nocturnal desaturation and the difference between predicted and measured DEE in apneic patients (r = -0.74, P < 0.05) and a similar negative trend with SMR (r = -0.65, P = 0.08). These preliminary data suggest that a nocturnal hypoxia may influence adaptive thermogenesis in apneic patients and complicate their body weight regulation.

[Genetic fingerprinting of inbred lines, outbred lines, transgenic individuals and 3T3 cells of Mus musculus with the probe B.E.S.T. MZ 1.3]. / Genetisches Fingerprinting von Inzuchtlinien, Auszuchten, transgenen Individuen und 3T3-Zellen von Mus musculus mit der Sonde B.E.S.T. MZ 1.3.

DNA samples from different inbred strains and F1-hybrids, from two outbred strains and from transgenic animals of the species Mus musculus were tested according to the "DNA fingerprint" technique (Jeffreys et al., 1985) using the B.E.S.T.-probe MZ 1.3 (Fa. Biotest, Frankfurt) and the restriction endonuclease Hinf I. In addition, the same method was applied to two cell types i.e. BALB/3T3 clone A 31 and 3T3 B-SV40. The DNA fingerprinting technique with probe MZ 1.3 proved to be a reliable method for genetic monitoring of different strains of mice. All inbred strains tested as well as their substrains could be identified and distinguished from each other without any doubt. Congenic and transgenic individuals, however, were identical with their background strains. After several in vitro passages, cells from cultures showed the similar DNA configuration as the donor strains. Within outbred strains, it was possible to quantify heterozygosity by the configuration of the DNA-patterns. These results suggest that it might be appropriate to replace the mathematically estimated inbreeding coefficient by so-called identity-coefficient (IK), which would depend on the probe and the restriction endonuclease used (e.g. IKMZ 1.3/Hinf I). Using the MZ 1.3 probe, the DNA fingerprint technique allows a unique genetic identification of different strains of mice and offers, furthermore, the possibility to use a colour kit rather than the usual P-32 marker.