Effect of traffic noise on the cyclical nature of sleep.

Sleep changes from shallow to deep and back again in a cyclical manner with a period of around 90 min. The sleep of 12 subjects, each sleeping for 24 nights, was monitored by EEG. The results indicate that the cyclical nature may be somewhat disturbed by continuous free-flowing traffic noise, at a level of 60 dB, if, for instance, waking is always considered as the end of one cycle. However, if a cycle is judged from a bird's-eye view of the sleep record, then it appears that the average subject persists in his normal cycle and the effect of noise is negligible. But individual differences are great and may even be in opposite directions [G. J. Thiessen and A.C. Lapointe, J. Acoust. Soc. Am. 64, 1078-1080 (1978)], which may result in obscuring real effects when data are averaged over a number of individuals. Defining a "sleep cycle" is of importance in view of reports [M. Herbert and R.T. Wilkinson, Proc. of Congress on Biological Effects on Noise, Dubrovnik, Yugoslavia (1973)] that the disturbance of the sleep rhythm has an effect on performance during the following day.

The efficacy of chlorine dioxide in controlling Salmonella contamination and its effect on product quality of chicken broiler carcasses.

A large spin-type chiller in an Ontario poultry processing plant was adapted so that the chill water could be treated with various levels of chlorine dioxide ( ClO2 ), increasing the concentration of ClO2 from 0 to 1.39 mg/liter resulting in reducing the bacteria count to the point where salmonellae could not be isolated from the chill water or the chilled broiler carcasses. In addition, coliform, psychrotroph , and aerobic plate counts were all greatly reduced (less than 1 log cycle) in chill water but were only slightly reduced (less than .5 log cycle) in macerated chicken broiler breast skin. Shelf-life was lengthened for broiler carcasses treated with 1.33 and 1.39 mg/liter ClO2 as compared to control carcasses. Sensory panelists reported no off flavors for any ClO2 concentration but rated broiler skin as being slightly lighter in color compared to control carcasses at all concentrations of ClO2 treatment.

Effect of continuous traffic noise on percentage of deep sleep, waking, and sleep latency.

When subjected to alternating quiet nights (32 dB) and noise nights (equivalent levels of 47 dB) a group of 14 subjects showed an average increase in the fraction of deep sleep of about 2.5% resulting from the traffic noise. Another group of 12 subjects whose noise nights were at 60 dB had an average of 4.6% increase in deep sleep during these nights. The number of wakings also increased for both groups but, as was found before, this adapted rapidly with the number of nights. The average latency of sleep onset does not appear to be affected by the traffic noise but individual differences are great and may be of opposite sign. Latency of sleep onset and waking both show appreciable "laboratory effect" which takes longer to disappear than the one or two nights usually assumed.

The evaluation of cell nuclei staining parameters regarding the reproducibility of fluorescence measurements.

The present methodological study is an attempt to optimize the staining parameters for a quantitative DNA determination of fluorescent cells. The application of pure dyes and a precise control of the staining procedure are preliminary conditions which have to be fulfilled, because the reproducibility of measurements is in this connection the most important criterion for a quantitative DNA related analysis of cell population. Chicken erythrocytes and isolated nuclei were applied as biological test objects. The staining procedure with acridine derivatives (acriflavine, proflavine, rivanol) was performed in accordance with the fluorescence-Feulgen reaction. The influence of staining parameters, such as (1) pH and (2) dye concentration of the staining solution, were evaluated regarding the spectral behaviour, the total fluorescence intensity, and the reproducibility of results.

Spectral changes of the fluorescent acriflavine--(Feulgen) DNA dye complex at different temperatures: application of a new cryostat for measurements in reflected and transmitted light.

The fluorometric behaviour of cellular objects is influenced during excitation by two nearly independent phenomena: (1) by the photochemical reaction of the DNA/AF dye complex, and (2) by the energy transfer among several DNA/AF dye complexes. Both processes show a distinct temperature-dependent behaviour and can therefore be characterized by the analysis of the fluorescence spectra at different temperatures. All microfluorometric measurements were performed with a self-constructed cooling device. The cryostat permits measurements of the cellular fluorescence within a range of temperatures between 4 K and 300 K. The cooling unit operates in accordance with the 'Continuous Flow Principle' and allows the application of objectives up to a numerical aperture of 0.6.

The development of a new technology for controlled cell fixation. A methodological pilot study.

Fixation in a traditional sense means the immersion of biological material into a chemical fluid. For permanent preservation (1) the fixative is always supplied in excess of the cell sample, and (2) the process of fixation is influenced by chemical impurities of the fixative fluid. Both factors influence the subsequent staining of cells. In order to avoid these uncontrolled influences, a new technology for controlled cell fixation has to be developed, whereby freshly prepared formaldehyde gas in an "inert" gas-flow of helium was applied to thin membranes by use of a capillary flow-in technique. The amount of fixative gas supplied, adsorbed, absorbed, diffused, and desorbed after saturation of the membranes could be reliably measured with an on-line operating "inert" mass spectrometer of the Omegatron type.

Effect of intermittent truck noise on percentage of deep sleep.

Sleep was divided into only two categories, "deep" and "shallow," the latter including waking, stage 1, and dreaming. For the sake of objectivity and precision the criterion was the level of alpha frequency and/or the audibility of spindles (from a speeded up tape recording of the EEG signals from frontal electrodes), which were timed by stopwatch. Twenty truck noises, presented every other night at peak levels of 65 dB (A-weighted), reduced deep sleep of 12, mainly young subjects by an average of 3%. Adaptation of the waking response occurs despite the separation of the noise nights by at least one quiet night. Adaptation to sleeping in the laboratory appears to continue for more than the one or two nights usually assumed.

A methodological study for the quantification and the control of the physico-chemical processes occurring during cell fixation. I. The development of a new technology.

Fixation in a traditional sense means the immersion of biological material into a chemical fluid. For permanent preservation the fixative is always "offered" (1) in excess of the cell sample, and the process of fixation is influenced by (2) chemical impurities of the fixative fluid. Both factors influence the succeeding dyeing of cells. In order to avoid these uncontrolled criteria, a new technology for controlled cell fixation has been developed, whereby freshly prepared formaldehyde and methanol gas in an "inert" gas-flow of helium was applied to thin membranes by aid of a capillary flow-in technique. The instrumental equipment consists of (1) an ultra-high vacuum flow-apparatus with a total-pressure measuring unit, (2) a gas-supply device, (3) a mass spectrometer including a pump system, and (4) a Teflon and/or glass-gas chamber for the treatment of synthetic (Hostaphan foils) or biological membranes (mesenterium) with formaldehyde as the fixative gas. The amount of "offered", adsorbed, absorbed, diffused, and desorbed fixative gas could be absolutely estimated after the saturation of the membranes with an "on-line" operating "inert" mass spectrometer of the Omegatron type. The gas treatment of the Hostaphan foils with formaldehyde showed that nearly all adsorbed gas molecules could be desorbed. In contrast to native membranes the greatest proportion of the gas molecules adhered to the biological surface, and only a small quantity were desorbable. Physisorption or physisorption and chemisorption occured depending on the adsorber surface property. A monolayer of formaldehyde of 5.10(14) to 1.10(15) molecules per 10(16) A2 surface area can be postulated on the basis of these preliminary results. This value corresponds to a mass of about 5.10(-8) g CH2O. It resulted in an area-coverage ratio of CH2O molecules per cell of 10(9):1. The membrane surface facing the gas side always amounted to 1 cm2. A fixative gas concentration of 10(6) molecules/cm3, and therefore a degree of coverage of less than 1/1000 monolayer can be estimated absolutely. For a precise determination of the degree of fixation, further experiments and the evaluation of additional physico-chemical parameters are necessary.

Disturbance of sleep by noise.

Young, middle-aged, and old subjects, 35 in all, were tested to determine the probability of disturbance of sleep, as judged by EEG records, by seven noises per night produced by a recording of a passing truck. There is roughly a linear relation with the A-weighted noise level. Young and old people have nearly the same response while middle-aged subjects are more sensitive by about 15 dB. This applies also to the probability of awaking. The probability of shifts in sleep to a shallower level does not appear to adapt in 24 successive nights with seven noises per night but the probability of waking drops to half value in about two weeks. Response increases with duration of the stimulus, at least over the limited range from fractions of a second to a minute.

The acridine dyes: their purification, physicochemical, and cytochemical properties. I. A purity test of some commercial acriflavine samples and the identification of their components.

The present investigation was designed to allow a critical comparison of the dye purity of six commercial acriflavine samples. Thin layer chromatography, absorption-, IR- and NMR-spectroscopy were applied for the identification of dye components and impurities. Ambiguities regarding the purity of the acriflavine samples have been resolved, showing that: (a) The finding permits the conclusion, that all analyzed samples of the fluorochrome "acriflavine" are characterized by a two-component dye pattern (acriflavine II and proflavine III), and contain fluorescent impurities. (b) The dye component III was the main component of only one dye sample. The effectiveness of these experiments is concerned with making automated microfluorometric measurement of cells stained with pure dye fractions more quantitative and reproduceable.

Effects of tritiated thymidine on cell population kinetics.

This paper reports growth-kinetic data of Chinese Hamster tissue culture cells exposed at various times to differnt activities (0.05 muCi/ml up to 10.0 muCi/ml of tritiated thymidine. The analysis of the results aims at the determination of colony-size distribution and to the cellular capacity of reproduction after treatment which is reflected in the cell division spectrum within dialy intervals. The results of the growth-curves represented were converted into integrated curves of colony-size distribution, and their alteration as exponential curves for estimation of the cell cycle as a function of culture time was established. The recovery process and course determination of population kinetics following the 3H-TdR-treatments were evaluated.

[Development and application possibilities of a computer-controlled microspectrophotometric system for cytoanalysis (CYTOS)]. / Entwicklung und Anwendungsmöglichkeiten eines rechnerge-steurerten mikrospektrophotometrischen Systems zur Zytoanalytik (CYTOS).

A computer-assisted microspectrophotometric system for quantitative cell identification and data conversion, based on the scanned intracellular image pattern, will be introduced. The CYTOS system was developed with high flexibility for the analysis of general morphological and physiological problems of cell recognition and classification. The investigation include the quantitative transformation of extinction values in relation to cytomorphologic and cytochemical properties of a cell. In order to objectivate the subjective impression of visible or non-visible information, contained in a microscopic image, the measured extinction values were transformed in color values by a special developed interface. Each color shade corresponds to the intracellular substance concentration. The results, presented, concentrate on the CYTOS methodology, its application to the translation of data cytograms of DNA containing chromatic structures, and the intra-cytoplasmatic distribution pattern of enzyms. The CYTOS method might be considered as a useful technique revealing discrimination factors of diagnostical value.