The Role of the Sympathoadrenomedullary System in the Formation of Pilot’s Adaptation to Flight Loads

The objective of this study was to evaluate the functions of the sympathoadrenomedullary system and the related psychophysiological reactions of pilots, depending on flying hours on a highly maneuverable aircraft. The study involved 78 volunteer pilots (41 high-maneuverability pilots and 37 bomber and transport aviation pilots). A set of methods was chosen with the possibility of their use according to the principle of comprehensive evaluation of the body functional state under flight loads taken into account. Our results indicate that highly maneuverable aircraft piloting induces a significant activation of the sympathoadrenomedullary system in pilots, compared to bombing and transport aircrafts. This is particularly common to young pilots with the total flying time of less than 1000 h. It has been recorded that changes in adaptation to the effect of flight factors on the body develop with age and flight experience.     

Evaluation of the Blood Circulation System in Pilots of Deck Aircrafts during Long-distance Missions

The goal of this study was to evaluate the state of cardiovascular system in fighter and helicopter pilots during a long-distance naval mission. The study was carried out aboard a heavy aircraft carrier in pilots of deck aircrafts, and its participants were represented by 17 fighter pilots, 9 helicopter pilots, as well as 21 flight operations controllers. The circulation indicators were studied by the method of volumetric compression oscillography, using an APKO-8 oscillometric analyzer of circulation. An AnnaFlash 2000 digital 24-h ECG accumulator was used to monitor the time course of heart rate (HR) in fighter and helicopter pilots flying off the deck of the carrier. The analysis of the central and peripheral hemodynamic indicators has shown a significant predominance of pilots with prehypertension and mild hypertension among the flight personnel of deck-based aviation. Maximal values of systolic, diastolic, and mean blood pressure prevailed in helicopter pilots, while minimal values were characteristic of fighter pilots. Differences in these parameters between helicopter and fighter pilots tended to increase gradually with the duration of the long-distance mission. Maximum HR increases (up to 157 bpm) were recorded in fighter pilots during landing on the carrier deck). The most stressful task for helicopter pilots proved to be the descent of a rescuer in a winch, which was evidenced by the HR values increasing up to 132 bpm. The indicators of adaptation to the conditions of a naval mission varied within wide ranges. Fighter pilots adapted themselves more successfully than helicopter pilots. Hence the conclusion about the necessity to upgrade the system of flight personnel selection and training for operating under the conditions of a long-distance naval mission, as well as the monitoring of the health state of pilots.     

Loss of consciousness as criterion of +Gz tolerance at Institute of Aviation Medicine MMA during +Gz acceleration selective test

+Gz induced loss of consciousness (G-LOC) is one of the most serious threats to aircrews flying high performance fighter aircraft. From the early beginning of use of our Centrifuge, use in selection was primary task. As a functional "endpoints" we use criteria: loss of peripheral vision, extreme pulse rate (above 180 b.p.m.), arrhythmias and loss of consciousness. The key-method in selection the candidate who tolerates +Gz stress on the best way is selection by common selective centrifuge "Test of linear increasing of acceleration" (TOLIA). We used gradual onset rate (GOR--0.1 G/s) and maximum/peak value: +5.5 Gz, +6.0 Gz and 7.0 Gz. Applied peak value depends on the goal of the test. The lowest peak value is for candidates planned for Air Academy, higher peak value is for those pilots planned for training to supersonic combat aircrafts and the highest peak value is for pilots who are planned to fly High performance combat aircrafts. We examined 2192 candidates in the last 20 years. Eleven subjects experienced G-LOC episodes. All episodes of G-LOC had occurred occasionally and without warning symptoms (loss of peripheral vision, gray out, blackout). The percentage of subjects having G-LOC episodes was 0.50%. Nine subjects experienced G-LOC during primary selection (+5.5 Gz), one G-LOC were observed at secondary selection (+6.0 Gz) and one G-LOC was observed during tertiary selection (+7 Gz). G-LOC is the only "endpoint" in the centrifuge selection which disqualifies the candidate at once and forever for planned flying duties. The other "endpoints" (loss of peripheral vision, heart rate above 180 b.p.m., arrhythmias) allow one more testing, not less than seven days later.     

How does time since feeding affect the fuels pigeons use during flight?

Time between meals can vary from multiple hours to days within and among species. We investigated the effects of time since feeding on lipid, protein, and carbohydrate oxidation in flying pigeons (Columba livia) by interpreting changes in blood plasma metabolite concentrations and mass during flight. Five pigeons were flown or rested for 4 h after food deprivations of 2, 12, 24, and 48 h. After flight, blood plasma concentrations of uric acid and beta-hydroxybutyrate were elevated over control and preflight values, indicating elevated protein and lipid catabolism during flight. Lipid oxidation, as indicated by changes in beta-hydroxybutyrate concentration, increased more in unfed flying pigeons compared with recently fed flying pigeons and with resting controls. Protein oxidation, as indicated by changes in uric acid concentrations, also positively covaried with feeding time; the covariation was mostly caused by increases in 48-h food-deprived pigeons. Unfed birds lost less mass during a 4-h flight than recently fed birds. We reasoned that recently fed pigeons oxidized more glycogen in flight than pigeons not recently fed; calculated glycogen stores explained 72%-117% of mass loss differences between 2- and 48-h-fed pigeons. Thus, time since feeding was an important determinant of the fuels pigeons used in flight.     

Increased levels of sister chromatid exchanges in military aircraft pilots

Sister chromatid exchanges (SCEs) were scored in lymphocytes of nine high-performance pilots of alphajet aircrafts and of ten control individuals from the same air base. Statistical analysis of the mean SCE count per cell in the total number of cells analyzed as well as in those having 12 or more SCEs (high-frequency cells, HFCs) revealed a significant difference between pilots and controls, after adjusting for the effect of smoking. Analysis of the cell cycle kinetic data (replication and mitotic indices) revealed no significant differences either between pilots and controls or between smokers and nonsmokers. Previously, we reported an increase in the SCE levels in workers of the aeronautical industry exposed to noise and whole-body vibration. The present results corroborate those findings and indicate that noise and whole-body vibration may cause genotoxic effects in man.     

Anion-binding centers of human serum albumin during an N-F conformation transition and in isolated albumin and blood serum

Fluorescent probe N-phenyl-1-amino-8-sulfonaphthalene (ANS) was used for studying pH-dependent structural N-F-transition in human serum albumin of two kinds: in commercial albumin and in natural blood serum. The kinetics of ANS fluorescence decay in albumin solutions was measured. There were found two types of the sites occupied by ANS in albumin under physiological conditions (pH 7.4). In the first binding site ANS fluorescence decay time was 16.6 +/- 0.3 nsec and it was not significantly changed at N-F transition (pH 4.0). In the second binding site the decay time was dependent on pH in commercial albumin and was not significantly changed in serum. In the second binding site there were individual differences of ANS decay time (4.3 +/- 0.6 nsec). The observed ANS fluorescence intensity enhancing (about 40-50%) in N-F transition may be explained by an increase of albumin binding sites capacity for ANS.     

Endothelial Dysfunction and Metabolic Effects of Nitric Oxide in Humans

Shortage of nitric oxide (NO) is believed to be a key factor in the development of endothelial dysfunction. Metabolic effects of NO were analyzed in subjects with multiple metabolic disorders (essential arterial hypertension, platelet hyperaggregability, and hypercholesterolemia). Effects of the NO-inducing ₁-adrenoblocker nebivolol on the blood rheology and lipid profile were studied in pilots regularly exposed to factors of flying work contributing to the development of endotheliocyte dysfunction. The dynamics of spontaneous platelet aggregation in pilots with arterial hypertension suggested that nebivolol produced a statistically significant general effect on platelets, reducing their baseline activation by eliminating endothelial dysfunction. This NO-inducing drug has an antiatherosclerotic effect. Metabolic effects of NO are essential for normalizing endothelial functions because this messenger interacts with key reactions of the pathogenic cascade in the cardiovascular continuum.     

Intracellular fluorescence decay time of anilinonaphthalene sulfonate

This paper presents the intracellular fluorescence decay time of the probe anilinonaphthalene sulfonic acid (ANS) and compares the results to certain ANS complexes in vitro. There is relatively constant decay time for intracellular ANS over a range of concentrations in the incubating medium, compared with marked variation in results with the complex of ANS-bovine serum albumin in vitro when concentration of the probe is varied. Calculation of the apparent rotational relaxation time from the Perrin equation, using ANS intracellular decay time and polarization data gave a tentative value of circa 66 ns. By comparison with the results of ANS complexes with cell fractions and with certain lipids these data support the concept that intracellularly the compound may be largely membrane located with a portion of the molecule in the lipid phase. Cells damaged by heating or alcohol show longer decay time than those which have taken up ANS in the living state. Suggestions for refinement of technique are included in the discussion.     

Flow cytometric detection of lymphocyte alterations in Huntington's disease

Several recent reports indicate that patients with Huntington's Disease (HD) may manifest membrane abnormalities in a wide variety of cells including peripheral blood lymphocytes. In this study, flow cytometry is used in conjunction with the fluorescent membrane probe, 8-anilino-1-naphthalene sulfonate (ANS), to examine peripheral blood lymphocytes from 16 HD patients and 14 age- and diet-matched control subjects. Increased ANS fluorescence intensity of lymphocytes (p less than 0.02) was found in HD patients as compared to control subjects. These differences are masked when the mean fluorescence of the total leukocyte population is measured, possibly explaining conflicting data of other investigators. These observed differences in ANS fluorescence intensity between HD patients and control subjects support the concept of a gene defect which may be expressed as membrane alterations in non-neural as well as neural cells. The selective alterations of lymphocytes may also reflect altered immunological activity reported in HD.     

Asymmetric membrane expansion and modification of active and passive cation permeability of human red cells by the fluorescent probe 1-anilino-8-napththalene sulfonate.

1. The membrane perturbations induced by the interaction of the fluorescent probe 1-anilino-8-naphthalene sulfonate (ANS) with human red blood cells were studied. 2. ANS below 0.5 mM inhibits partially (20% maximum) the ouabain-insensitive Na+ and K+ influx and efflux. Above 0.5 mM ANS increases both Na+ and K+ leak fluxes. The increased cation leaks are larger for Na+ than K+. 3. The (Na+ +K+)-ATPase and ouabain-sensitive Na+ and K+ fluxes are inhibited by ANS. Ouabain-insensitive, Mg2+-dependent ATPase activity of ghosts is stimulated by [ANS] less than 0.3 mM and inhibited by [ANS] greater than 0.3 mM. 4. ANS also inhibits the Na+-dependent, ouabain-insensitive K+ influx that is inhibited by ethacrynic acid and furosemide. 5. Red cells become crenated with [ANS] less than 1 mM and sphere at [ANS] greater than 1 mM. In the former conditions hypotonic hemolysis is decreased whereas the latter increase osmotic fragility. 6. It is suggested that ANS expands the membrane asymmetrically by binding preferentially to the external membrane surface. 7. It is concluded that ANS is a general inhibitor of ion transport, particularly of those processes thought to involve facilitated-diffusion mechanisms. The increased cation leaks observed at high ANS concentrations may be related to prehemolytic membrane disruption. 8. The membrane perturbations caused by ANS are compared to those caused by other reversible inhibitors of anion exchange in red blood cells. Their possible modes of action are discussed.     

Effects of low-intensity laser irradiation on the state of blood proteins

The action of a low-intensity 632.8 nm-wavelength laser radiation on blood elements was studied. The degree of binding the fluorescence probes 1.8 ANS by blood proteins and cells was taken to be the index of the response to irradiation. The change of fluorescence of the oppositely charged probes indicates that a He-Ne laser radiation causes processes leading to a change of charge in proteins of a blood plasma with the negative charge decreased in most cases. The effect depends on individual characteristics of a biological object, on the exposure dose and the incubation time following the irradiation.     

Sympathetic nerve regulation of cochlear blood flow during increases in blood pressure in humans

The purpose of this work was to show that regulation of the blood flow to the cochlea by the sympathetic nervous system occurs in humans at the level of the cochlear microcirculation during increases in blood pressure and that its involvement depends on the pressure level. Eight anaesthetized patients undergoing tympanoplasty for hearing disease took part in a pharmacological protocol of stimulation and inhibition of the autonomic nervous system (ANS) to provide variations in systolic blood pressure (BP_S) and cochlear blood flow (CBF). The CBF was measured by laser-Doppler flowmetry. Changes in autonomic nerve activity were brought about by changes in baroreceptor activity (BR) initiated by the injection of an α adrenergic agent before and after sympathetic and parasympathetic blockade. The CBF variations (δCBF) were plotted against BP_S increases at each stage of the ANS inhibition. The BR diminished significantly after α blockade, after α and β blockade, and after α and β blockade and atropine, by 50% (P < 0.01), 29% (P < 0.05), and 95% (P < 0.001) respectively. The BP_S increased significantly (P < 0.01) by 36 (SD 9)%, 47 (SD 1)%, and 67 (SD 16)% respectively. The CBF response to an increase in BP_S exhibited two opposing variations in the patients: CBF decreased significantly in one group, and increased significantly in the other group. In both groups, δCBF decrease and δCBF increase, respectively, were significant after ANS blockade; even so the decrease and increase, respectively, levelled off at BP_S around 160 mmHg before ANS blockade. For BP_S below 160 mmHg, correlations between δCBF and BP_S were significant before inhibition and after inhibition of ANS. For BP_S above 160 mmHg, BP_S and δCBF were not correlated before inhibition of ANS, and were significantly correlated after inhibition of ANS. For BP_S below 160 mmHg, CBF response to the BP_S increase was the same before and after ANS blockade, i.e. ANS control did not predominate; even so, for BP_S above 160 mmHg, the CBF response to BP_S increase was different before and after ANS blockade: CBF varied significantly after ANS blockade as it varied for BP_S below 160 mmHg, while it remained constant before ANS blockade that elicited ANS control of CBF. In conclusion, sympathetic nerve regulation via its vasomotor tone at the level of cochlear microcirculation occurred markedly when the blood pressure was above 160 mmHg; the autonomic nervous system would appear to control the cochlear blood flow against large variations in blood flow in response to hypertensive phenomena. Accepted: 7 October 1996     

Interaction of the organic anion 1-aniline 8-naphthalene sulfonate (ANS) with isolated rat hepatocytes

The interaction of ANS with rat hepatocytes in time was studied by fluorescence spectroscopy. The intercept of the first linear portion of the time curve of interaction showed a positive value over all the ANS concentration range employed. This value was maintained after cellular disruption by homogenization. It was affected by ionic strength, pH, and divalent cation in the incubation medium, all conditions affecting the cellular surface. These data suggest that this phenomenon might be a binding of the compound to the hepatocytes surface. Due to the time constant and its disappearance after cellular disruption the other slower component of the curve seems to correspond to a process of translocation across the membrane.     

Flight of the Chinese white pine beetle (Coleoptera: Scolytidae) in relation to sex, body weight and energy reserve

The flight distance, flight time and individual flight activities of males and females of Dendroctonus armandi were recorded during 96-h flight trials using a flight mill system. The body weight, glucose, glycogen and lipid content of four treatments (naturally emerged, starved, phloem-fed and water-fed) were compared among pre-flight, post-flight and unflown controls. There was no significant difference between males and females in total flight distance and flight time in a given 24-h period. The flight distance and flight time of females showed a significant linear decline as the tethered flying continued, but the sustained flight ability of females was better than that of males. The females had higher glycogen and lipid content than the males; however, there was no significant difference between both sexes in glucose content. Water-feeding and phloem-feeding had significant effects on longevity, survival days and flight potential of D. armandi, which resulted in longer feeding days, poorer flight potential and lower energy substrate content. Our results demonstrate that flight distances in general do not differ between water-fed and starved individuals, whereas phloem-fed females and males fly better than water-fed and starved individuals.     

Effects of chronic exposure of high-sustained +Gz-accelerations on pulmonary function

The development of prospective aircrafts with more performant flight characteristics has challenged the investigations of remote sequelae of unfavorable effect of high-sustained +Gz-accelerations on human pilot. For some last years we have conducted a set of exploratory works, which entailed the experimental investigations on animals, the centrifuge exposures on volunteered test-subjects and flying tests in aerial combat maneuvering, aimed at study of chronic effects of high-sustained +Gz-accelerations on pulmonary function of animals and humans.     

Interaction of the fluorescent probe, 1-anilino-8-napthalene sulfonate, with the sulfate transport system of Ehrlich ascites tumor cells.

The addition of the fluorescent dye, ANS, to intact ascites tumor cells results in an enhancement of fluorescence intensity. The increase in fluorescence intensity as a function of time is biphasic which suggests that at least two processes occur. The first associated with the rapid initial rise in fluorescence represents binding to the cell surface while the second or slower phase reflects entrance of ANS into the intracellular phase. The relationship between bound and free ANS in 0.50 mM sulfate medium was used to calculate the apparent dissociation constant of ANS-membrane complex (Kd = 6.53 times 10(-5) M) and the total number of ANS binding sites (4.49 nmoles/mg dry weight). Kinetic analysis of steady state sulfate transport in the presence and absence of ANS suggests that (1) sulfate exchange can be described by Michaelis Menten type kinetics (Km = 2.05 times 10(-3) M), (2) a small fraction of surface associated ANS competitively inhibits sulfate exchange (Ki = 4.28 times 10(-6) M) and (3) the transport system has a higher affinity for ANS than for sulfate. These data are consistent with the hypothesis that inhibition of sulfate exchange is related to the direct, reversible interaction of the negatively charged sulfonate group of ANS with superficial positively charged membrane sites.     

Conflicting traffic: characterization of the hazards of birds flying across an airport runway

Bird–aircraft collisions cost millions of dollars to aviation globally and cause deaths. We designed and tested a protocol to study the hazards to aircraft from birds flying across runways where aircraft rotate and climb during take‐off. We recorded birds and flight height of birds flying across runway 03L at OR Tambo International Airport, South Africa. A total of 7,938 birds of pigeon size or larger crossed a 400 m length of runway during 14 h and 15 min, a rate of 8.8 birds per minute; there were 200 aircraft taking off during this period. The biggest bird–aircraft collision hazard is posed by African Sacred Ibis and Grey‐headed Gull. Respectively, these species contribute a mean of 111 kg per 10 min and 47.2 kg per 10 min biomass flying across the runway. We identify possible management options to reduce the hazard of bird–aircraft collisions. Our survey protocol and data treatment is easy to use, will add additional and important definition to existing activities to reduce bird–aircraft collisions and can provide comparable hazard information to aerodrome authorities and pilots.     

Heart Rate and Respiration Responses to Real Traffic Pattern Flight

The purpose of this study was to observe heart rate and respiration responses to real traffic pattern flight. Nine experienced and nine less-experienced military pilots on active flying status participated in four uninterrupted traffic patterns flight missions with F-7 jet trainer. The heart rates and respiration waves were continuously recorded using a small recording device strapped around the chest. As compared with baseline values, significant increases in heart rates of the two groups (for experienced pilots group, F (11, 88) = 4.636, p = 0.000; for less-experienced, F (11, 88) = 4.437, p = 0.000) and mean respiration rates of less-experienced group (F (11, 88) = 4.488, p = 0.000) were obtained during the phases of take-off, final approach and landing. Heart rates of less-experienced pilots were significant higher than those of experienced pilots during the take-off phase (p < 0.05). There were no significant differences in respiration rates between the two groups at each phase of the whole flight. The results show that take-off, final approach and landing are the most mental workload phases in-flight, and less-experienced pilots show more mental workload than experienced pilots in take-off phase in-flight.     

Effects of chiral fragrances on human autonomic nervous system parameters and self-evaluation

The effects of chiral fragrances (enantiomers of limonene and carvone) on the human autonomic nervous system (ANS) and on self-evaluation were studied in 20 healthy volunteers. Each fragrance was administered to each subject by inhalation using an A-A-B design. Individuals were tested in four separate sessions; in one session one fragrance was administered. ANS parameters recorded were skin temperature, skin conductance, breathing rate, pulse rate, blood oxygen saturation and systolic as well as diastolic blood pressure. Subjective experience was assessed in terms of mood, calmness and alertness on visual analog scales. In addition, fragrances were rated in terms of pleasantness, intensity and stimulating property. Inhalation of (+)-limonene led to increased systolic blood pressure, subjective alertness and restlessness. Inhalation of (-)-limonene caused an increase in systolic blood pressure but had no effects on psychological parameters. Inhalation of (-)-carvone caused increases in pulse rate, diastolic blood pressure and subjective restlessness. After inhalation of (+)-carvone increased levels of systolic as well as diastolic blood pressure were observed. Correlational analyses revealed that changes in both ANS parameters and self-evaluation were in part related to subjective evaluation of the odor and suggest that both pharmacological and psychological mechanisms are involved in the observed effects. In conclusion, the present study indicates that: (i) prolonged inhalation of fragrances influences ANS parameters as well as mental and emotional conditions; (ii) effects of fragrances are in part based on subjective evaluation of odor; (iii) chirality of odor molecules seems to be a central factor with respect to the biological activity of fragrances.     

Cumulative plot of heart rate variability spectrum assesses kinetics of action of cholinergic drugs in rats

A new approach to assess autonomic nervous system (ANS) activity and its response to drug action is presented. Our approach is based on the use of a cumulative plot of data obtained by power spectral analysis of heart rate variability, in defined frequency bands, during short time epochs (e.g., 2 min in rats). The substantial temporal variability in power evolving from the constant balancing nature of the ANS activity is minimized by this approach and produces a measurable index of ANS activity vs. time. The cumulative plot emphasizes the temporal response pattern of different components of the ANS and thereby facilitates the investigation of the kinetics of action of drugs affecting the ANS. We used this method to measure the activity of cholinergic drugs in freely moving Sabra rats. Bolus atropine doses between 0.5 and 2 mg/kg produced a similar magnitude of effect, reduction of the ascending slope by 0. 003 power units/h, whereas the duration of this effect was dose dependent. A lower atropine dose (0.1 mg/kg) or 0.5 mg/kg scopolamine elevated the slope (0.074 and 0.054 power units/h for 206 and 216 min, respectively). The method was used similarly to assess the interaction between cholinergic drugs. Pretreatment with pyridostigmine produced temporal blockage of the anticholinergic activity of atropine.