Pulse oximetry--a non-invasive method for direct and continuous monitoring of oxygen saturation and pulse rate--comparative studies with blood gas analysis and hemoreflectometry in the dog, swine and sheep

The use of pulse oximeters as a non-invasive, real time and online method for the continuous monitoring of oxygen saturation is discussed and compared to other methods like hemoreflectometry, and blood gas analysis. Analyses of linear regression show extraordinarily good correlations between all three monitoring systems. Pulse oximetry and hemoreflectometry on the one hand and blood gas analysis on the other hand sometimes show quite differing values of oxygen saturation. This phenomenon is due to the fact that the measuring methods are based on different working principles as well as it can be explained by the various hemoglobin-types. The pulse rate also measured by the pulse oximeter is nearly completely identical to the heart rate of the ECG. A slight temporal delay between the two acoustic signals is noticed and justified. Pulse oximetry seems to be superior to other oxygen monitoring systems because of its continuous noninvasive measuring technique.     

The development of cytogenetic research at the Plant Breeding Institute Halle/Hohenthurm with special reference to aneuploidy in cereals

Summary The historical development of cytogenetic research in cereals performed at the Plant Breeding Institute of the Martin-Luther-University Halle-Wittenberg from its beginning in 1935 until 1992 is reviewed with special reference to polyploidy, alien introgression and aneuploidy.Th. Roemer founded 1935 in the framework of his Institute a Department of Mutation Research which, in 1937, was extended to a Department of Cytogenetics with R. Freisleben as the first head. Research highlights of this period were the introduction of mutation breeding, the development of autotetraploids in barley and linseed, the discovery of the crossability genes in wheat and the performance of wheat-rye crosses.The main objective in the period between 1950–1960 was the analysis of the relationships between chromosome behaviour and seed set in tetraploid rye and octoploid triticale.Since 1961 the Cytogenetics Research Group was headed by D. Mettin; he was followed by W.D. Blüthner in 1983. The research activities in this period concerning aneuploidy in rye and wheat and alien introgression are being reviewed under the following headings: Cytogenetics of rye; work with wheat aneuploids; contributions to the IR introgression into wheat; alien introgressions into wheat to improve disease resistance and grain quality; the exploitation of molecular markers.     

Concentrations of prolactin, LH, estradiol-17 beta and progesterone in swine after biotechnical stimulation with PMSG, HCG and suidor]

Concentrations of estradiol-17 beta, progesterone, luteinising hormone (LH), and prolactin were recorded from 9 gilts, following cycle blocking by means of Suisynchron(R)-Pr?mix and application of PMSG, HCG, and Suidor(R). A radio-immuno-assay which for its quality criteria enabled safe determination of the hormone in peripheral blood had been worked out specifically for prolactin appraisal. HCG application led to blockage of pre-ovulatory LH release in 7 of 9 animals. Possible causes are discussed. Prolactin concentrations during oestrus were differentiated and, for example, were characterised by strong oscillatory variations. With the experimental arrangement used, the boar pheromone Suidor(R) was not found to have any impact upon hormone profiles.     

Structural and functional effects of early exposure to estradiol-17β and 17α-ethynylestradiol on the gonads of the gonochoristic teleost Dicentrarchus labrax

This study investigated the effects of estrogens on sexual differentiation in sea bass (Dicentrarchus labrax L.), a gonochoristic marine teleost that under culture conditions has a histologically sexual undifferentiated period that covers most of the first year of life, after which most individuals develop as males. Sea bass that had no noticeable histological sign of sex differentiation were fed estrogens at two doses (5 or 10 mg kg^-1 food) and for different periods ranging from 48 to 426 days post fertilization (DPF). Exposure to the synthetic estrogen 17-ethynylestradiol (EE₂) at 10 mg kg^-1 food from 60 to 260 DPF, including the sensitive period to equivalent doses of synthetic androgens previously determined for this species (126-226 DPF), significantly (p < 0.05) more than doubled the number of juvenile females to 80%, compared to the control value of 33%, and completely suppressed gonadal development in the remaining 20% of the population. This suggests that the period during which sea bass gonads exhibit high sensitivity to androgens is also very sensitive to estrogens. A comparable exposure to the natural estrogen estradiol-17 (E₂) resulted in 13% of the fish having suppressed gonadal development, but induced 57% of the fish to develop gonads with germinal tissue of both sexes, suggesting a pivotal role for E₂ during this sensitive period. Earlier exposure to EE₂ at 10 mg kg^-1 food from 48-88 DPF, significantly (p < 0.05) increased the number of females to 62% from 36% in the control group, allowing for the normal testicular development in the remaining fish. In contrast, a later chronic exposure (226-426 DPF) to E₂, at either 5 or 10 mg kg^-1 food, starting when the gonads showed no sign of sexual differentiation but past the critical sensitive period, had no effect on the resulting overall sex ratios, indicating that after this period responsiveness of the gonads to estrogens decreases as gonadal sexual differentiation progresses. However, the consequences of this apparently innocuous exposure were later manifested in adults, exemplified by a significant dose-dependent reduction in the number of mature males at 626 DPF, coinciding with the second reproductive season, the time when males normally reach sexual maturation in cultured sea bass. This suggests that chronic exposure to E₂ past the critical sensitive period may not affect the sex ratio, but could result in alterations in the male reproductive organs. This was later verified by histological analysis which revealed a significant (p < 0.05) dose-dependent reduction of the surface of the testicular lobules in the remaining males that did not mature. Together, these experiments illustrate both readily observable and subtle effects of estrogens on sex proportions, gonadal morphology and maturation rates, providing evidence that estrogen exposure can have delayed action in a teleost in a manner similar to the effects described for mammalian species. The possible existence of effects of this latter type in adult fish could be considered when evaluating the consequences of deliberate or accidental exposure to estrogens or putative estrogenic chemicals, particularly if such exposure had taken place during sex differentiation.     

Susceptibility of cider apple cultivars to the sooty blotch and flyspeck complex in Spain

Cultivar may be an important factor associated with the occurrence and severity of sooty blotch and flyspeck (SBFS) fungi in apple. The aim of the study was to analyse the influence of 28 cultivar features on the occurrence of the SBFS complex in apple and to categorize the importance of each using a multivariate approach. Features were classified as agronomic (related to fruiting and growing behaviour and to susceptibility to other diseases; 11 features), morphological (describing fruit morphology; 11) and technological (related to the chemical composition of the fruit juice; 6). Susceptibility to SBFS varied widely among cultivars. The predictive value of some features was not the same for the signs of SB and FS, possibly because each sign is produced by a different species complex which may behave differentially against environmental variables, including the cultivar. Our results showed that agronomic features as a whole were more significant than morphological or technological ones for explaining the cultivar variability in damage. Those related to fruit development phenology were the more explanatory among the agronomic features: late-maturing cultivars suffered higher damage. The intensity of colour was the most explanatory variable among the features describing fruit morphology, showing that SBFS severity was greater on light-coloured apples. Russeting level or skin texture, amongst other variables, were significant but less predictive. The technological features were least explanatory: FS damage was favoured by lower sugar content and higher phenol content at harvest, whereas variability in SB signs was not explained by any juice parameter. The multivariate approach allowed us to select the most important variables in relation to SBFS damage and to discard those without influence, which may be a valuable contribution to understand SBFS development. This research highlights the need of a proper choice of cultivar to reduce disease severity.     

The significance of mycotoxin assimilation for the contamination of milk and milk products

The two possible pathways contaminating milk and milk products with mycotoxins are either the secretory or post-secretory route. The latter is of only little importance due to cooling conditions in production and storage. A secretory contamination can only occur with such mycotoxins, which undergo no complete degradation through their passage into the milk. From the mycotoxins, present in cow's feed; virtually only aflatoxin B1 yields a milkborne metabolite, the aflatoxin M1. The carry over rate is low (2 +/- 1%), but can be enhanced by polyhalogenated biphenyls, also present in the forage. Under normal conditions, however, this enhancement will not be measurable due to low equimolar concentrations of both reactants. The aflatoxin M1 content in herd's bulk milk depends exclusively on the content of the precursor aflatoxin B1 in the ration of the cow and is with less than 10 ng/kg fairly low at present in the Federal Republic of Germany. A careful supervision of the imported feed ingredients for mixed feed, however, will ensure to keep those batches out of dairy cow feeding which exceed a certain level of aflatoxin. The legal threshold is 10 micrograms/kg, being even too high to ensure a milk containing less than 10 ng/kg under high energy feeding conditions. The discussed thresholds for aflatoxin M1 in milk are 50 and 10 ng/kg resp., the latter value is scheduled for milk used in infant nutrition. To keep this low concentration the intake of aflatoxin B1 must be less than 2 micrograms/kg of the daily ration.     

The effect of steroid hormone doses after ovariectomy on the peripheral hormone processes and uterine development in gilts. 2. Effects on gilts during early pregnancy

Experimental studies were conducted into ovariectomized pregnant gilts to establish effects of exogenic hormone administration, with endogenic ovarian steroids excluded, upon uterus and fetus development as well as on hormone levels in blood plasma, endometrium, and allantoic fluid. Hormone concentrations in blood plasma were found to depend clearly on hormone doses applied after ovariectomy to preserve pregnancy. 2 to 3 weeks of smooth gravidity, following ovariectomy, were ensured on the 6th or 14th day after KB1 by daily application of very low doses of progesterone only (80 mg) or in combination with estrogens, the ratio being 480:1.