Heart rate, respiratory rate, apnoeas and peripheral arterial oxygen saturation in healthy term neonates during quiet sleep.

AIM: This study compiled percentiles for cardiorespiratory parameters in healthy term neonates during quiet sleep. METHODS: We enrolled 215 healthy term neonates born at Hannover Medical School, Germany, between October 2011 and March 2013. They were prospectively observed on the maternity ward at a median age of two days using six-hour recordings of pulse oximeter plethysmography, oxygen saturation, thoracic breathing movements and electrocardiogram during sleep in a supine position. We examined their heart rate, respiratory rate and oxygen saturation during quiet sleep, plus bradycardias, apnoeas lasting at least four-seconds and desaturations below 85%. RESULTS: The 3rd, 50th and 97th percentiles were calculated as follows: heart rate 87, 112 and 133 beats per minute, respiratory rate 32, 44 and 57 per minute and oxygen saturation 94, 98 and 100%. Desaturations, apnoeas and bradycardias below 80 beats per minute were common and recorded in 54%, 98% and 30% of participants. In contrast, only 7% experienced bradycardias of less than two-thirds of the baseline heart rate and 5% experienced apnoeas exceeding 15 seconds. CONCLUSION: Our results will facilitate the evidence-based valuation of cardiorespiratory parameters in term neonates and help validate the significance of cardiorespiratory events in preterm infants at discharge.

Substitution pattern on anthrol carbaldehydes: excited state intramolecular proton transfer (ESIPT) with a lack of phototautomer fluorescence.

Photophysical properties and excited state intramolecular proton transfer (ESIPT) reactivity for anthrol carbaldehydes 1-5 have been investigated computationally and experimentally by steady-state and time-resolved fluorescence and laser flash photolysis (LFP). 1,2-Disubstituted anthrol carbaldehydes 1 and 2 are not ESIPT reactive, contrary to naphthol analogues. The main deactivation channels from S1 for 1 and 2 are fluorescence (ΦF = 0.1-0.2) and intersystem crossing (ISC) to almost isoenergetic T2 states. The triplet states from 1 and 2 were detected by LFP (in N2-purged CH3CN, τ = 15 ± 2 µs for 1, and τ = 5.5 ± 0.1 µs for 2). In contrast, 2,3-disubstituted anthrols 3-5 undergo efficient barrierless ultrafast ESIPT. However, the typical dual emission from locally excited states and ESIPT tautomers were not observed since ESIPT proceeds via a conical intersection with S0 delivering the keto-tautomer in the hot ground state. Therefore, anthrols 3-5 are about ten times less fluorescent compared to 1 and 2, and the emission for 3-5 originates from less-populated conformers that cannot undergo ESIPT. Keto-tautomers for 3-5 were detected in CH3CN by LFP (λmax = 370 nm, τ = 30-40 ns). The difference in ESIPT reactivity for 1-3 was fully disclosed by calculations at ADC(2)/aug-cc-pVDZ level of theory, and particularly, by calculation of charge redistribution upon excitation to S1. Only 2,3-disubstituted anthrols exhibit polarization in S1 that increases the electron density on the carbonyl and decreases this density on the phenolic OH, setting the stage for ultrafast ESIPT.

Ventilatory long-term facilitation in unanesthetized rats.

We tested the hypothesis that unanesthetized rats exhibit ventilatory long-term facilitation (LTF) after intermittent, but not continuous, hypoxia. Minute ventilation (VE) and carbon dioxide production (VCO(2)) were measured in unanesthetized, unrestrained male Sprague-Dawley rats via barometric plethysmography before, during, and after exposure to continuous or intermittent hypoxia. Hypoxia was either isocapnic [inspired O(2) fraction (FI(O(2))) = 0.08--0.09 and inspired CO(2) fraction (FI(CO(2))) = 0.04] or poikilocapnic (FI(O(2)) = 0.11 and FI(CO(2)) = 0.00). Sixty minutes after intermittent hypoxia, VE or VE/VCO(2) was significantly greater than baseline in both isocapnic and poikilocapnic conditions. In contrast, 60 min after continuous hypoxia, VE and VE/VCO(2) were not significantly different from baseline values. These data demonstrate ventilatory LTF after intermittent hypoxia in unanesthetized rats. Ventilatory LTF appeared similar in its magnitude (after accounting for CO(2) feedback), time course, and dependence on intermittent hypoxia to phrenic LTF previously observed in anesthetized, vagotomized, paralyzed rats.

Use of styrene radical cations as probes for the complexation dynamics of charged guests with alpha- and beta-cyclodextrins.

The complexation dynamics of radical cations with cyclodextrins (CD) was studied using photophysical techniques. Radical cations of 4-vinylanisole and trans-anethole were formed within alpha- and beta-CD cavities by two-photon photolysis of the respective styrene precursors. Exit of the radical cations from alpha-CD complexes with 1: 1 and 1:2 (guest: CD) stoichiometries and beta-CD complexes with 1:1 stoichiometries occurred with lifetimes shorter than 100 ns. Most of the radical cations formed escape from the CD cavities, but a small portion do react with alpha-CD when this host is present in high concentrations.

Application of time-resolved diffuse reflectance techniques in studies of reaction intermediates in suspensions of Bacillus subtilis.

Short lived reaction intermediates such as triplet states and free radicals can be detected in vivo using laser photolysis techniques with time-resolved diffuse reflectance detection. This novel approach is illustrated for bacterial suspensions of Bacillus subtilis.

Transient state kinetics of the reactions of isobutyraldehyde with compounds I and II of horseradish peroxidase.

Elementary reactions have been studied quantitatively in the complex overall process catalyzed by horseradish peroxidase whereby isobutyraldehyde and molecular oxygen react to form triplet state acetone and formic acid. The rate constant for the reaction of the enol form of isobutyraldehyde with compound I of peroxidase is (8 +/- 1) X 10(6) M-1 s-1 and with compound II (1.3 +/- 0.3) X 10(6) M-1 s-1. Neither the enolate anion nor the keto form is reactive. The reactivity of enols with peroxidase parallels that of unionized phenols and a common mechanism is proposed. The overall catalyzed reaction of isobutyraldehyde and oxygen consists of an initial burst followed by a steady state phase. The burst is caused by the following sequence: 1) an initial high yield of compound I is formed from reaction of native enzyme with the autoxidation product of isobutyraldehyde, a peracid and 2) compound I rapidly depletes the equilibrium pool of enol which is present. After this burst a steady state phase is observed in which the rate-limiting step is the conversion of the keto to the enol form of the aldehyde catalyzed by phosphate buffer. The rate constant for the keto form reacting with phosphate is (8.7 +/- 0.6) X 10(-5) M-1 s-1. All constants were measured in dilute aqueous ethanol at 35 degrees C, pH 7.4, and ionic strength 0.67 M. Both the initial burst of light and the steady state emission from triplet acetone can be observed with the naked eye. Since the magnitude of the burst is a measure of the equilibrium amount of enol, the keto-enol equilibrium constant is readily calculated and hence also the rate constant for conversion of enol to keto. The keto-enol equilibrium constant is unaffected by phosphate which therefore acts as a true catalyst.

Chlorophyll: an efficient detector of electronically excited species in biochemical systems.

Micelle-solubilized chlorophyll efficiently detects electronically excited species generated in enzymatic systems. In most, if not all, systems the chemiexcited species is formed in the triplet state; chlorophyll fluorescence is observed as result of energy transfer. Red emission can also be elicited from chlorophyll in chloroplasts or bound to microsomes.

Peroxidase-catalyzed formation of triplet acetone and chemiluminescence from isobutyraldehyde and molecular oxygen.

It has been established that the horseradish peroxidase/O2/isobutyraldehyde (IBAL) system leads to triplet acetone and formic acid formation followed by phosphorescence of the triplet acetone (see, for example, Bechara, E.J.H., Faria Oliveira, O.M.M., Durán, N., Casadei de Baptista, R., and Cilento, G. (1979) Photochem. Photobiol. 30, 101-110). In this paper many of the mechanistic details are established. The reaction is initiated by the autoxidation of IBAL to form the peracid (CH3)2CHC = O(OOH). The peracid converts horseradish peroxidase into compound I which in turn is converted into compound II by abstracting the alcoholic hydrogen atom from the enol form of IBAL. This creates a free radical with two resonance forms. (Formula: see text) Addition of molecular oxygen to the latter resonance form creates a peroxy radical which abstracts a hydrogen atom near the active site of the enzyme. The newly formed alpha-peroxide in turn forms a dioxetane-type of intermediate which rapidly decomposes into triplet acetone and formic acid. Compound II reacts with the enol by the same pathway as compound I. Thus native horseradish peroxidase is regenerated. The hydrogen atom abstraction near the enzyme active site may occur directly from ethanol, present to solubilize IBAL or from a group on the enzyme, in which case ethanol participates in a repair mechanism. Phosphate buffer is necessary because it catalyzes the keto-enol conversion of IBAL. Thus horseradish peroxidase participates in a normal peroxidatic cycle. The only chain reaction is the uncatalyzed autoxidation of IBAL, most of which occurs prior to the mixing of IBAL with the oxygenated horseradish peroxidase solution.

On the mechanism of peroxidase-catalyzed chemiluminescence from isobutyraldehyde.

The reaction of isobutyraldehyde with dissolved oxygen catalyzed by horseradish peroxidase has been studied from the standpoint of determining the rate-limiting factor under a variety of conditions. Chemiluminescence from the product triplet acetone and rate of oxygen uptake were determined in simultaneous experiments. The reaction is initiated by the peracid obtained from the uncatalyzed autoxidation of the aldehyde; and under certain conditions the amount of peracid is also rate-limiting in the steady-state portion of the reaction. Under other conditions the total amount of enzyme and under still others the rate of formation of enol from the parent aldehyde controls the rate.

Rocketborne cryogenic (10 K) high-resolution interferometer spectrometer flight HIRIS: auroral and atmospheric IR emission spectra.

A Michelson interferometer spectrometer cooled to 10 degrees by liquid helium was flown into an IBC class III aurora on 1 April 1976 from Poker Flat, Alas. The sensor, HIRIS, covered the spectral range 455-2500 wave numbers (4-22 microm) with a spectral resolution of 1.8 cm(-1) and an NESR of 5 x 10-12 W/cm2 scrm(-1) at 1000 cm(-1). An atmospheric emission spectrum was obtained every 0.7 sec over an altitude range of 70-125 km. Atmospheric spectra were obtained of CO2 (nu3), NO (Deltanu = 1), O3 (nu3) and CO2 (nu2). Auroral produced excitations were observed for each band, this being the first known measurement of auroral enhancements of O3 (nu3), 9.6 microm, and CO2 (nu2), 15 microm, emissions.