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PubMed2002

A system for monitoring heart pulse, respiration and posture in bed.

A non-invasive system has been developed to monitor cardiac vibrations, respiration and posture of inbed hospitalized patients and elderly people who need constant care. These physiological variables are recorded by four 2 x 28 cm piezoelectric film acceleration sensors, eight 2 x 2 cm small pressure sensors and a 5 x 100 cm long pressure sensor. The piezoelectric sensors, attached to the chest over the heart during bed sleep or rest, detect the movements produced by the heartbeat and respiration. The eight small pressure sensors are attached at various positions on the upper and lower body. A longer pressure sensor, to detect the patient leaving the bed, is attached to the side of the bed. These sensor outputs are digitized at a sampling rate of 200 Hz using a 12-bit A/D converter and stored on a personal computer. The computer detects cardiac vibrations and respiration from upper chest movements and posture from the pressures recorded by small and long pressure sensors.

Bed Rest↗

PubMed1994

Spinal evoked potentials are predictive of neurologic function in a porcine model of aortic occlusion.

The limitations of somatosensory evoked potentials during aortic occlusion stimulated us to evaluate the sensitivity and specificity of spinal (T10 and L4) evoked potentials (SpEPs) in predicting neurologic function after aortic occlusion. Thirty-six swine were assigned randomly to three equal groups (Group 1, control; Group 2, cerebrospinal fluid (CSF) drainage; Group 3, CSF drainage with 20-mg intrathecal papaverine). After induction of anesthesia and initiation of physiologic monitoring, a left-sided thoracotomy was performed to provide access to the descending aorta. SpEPs were generated by stimulating the thoracic spinal cord and recording the conducted response at the T10 and L4 level. After baseline measurements were recorded, the descending aorta was occluded 1 cm distal to the left subclavian artery. SpEPs were recorded every 2.5 min and physiologic variables every 5 min. The aorta was unclamped 10, 15, or 20 min after loss of the L4 SpEP. If the L4 SpEP was not lost, the aortic occlusion interval was terminated at 90 min. Attenuation of the SpEPs occurred earlier at the L4 level. Group 1 experienced the earliest loss of the L4 SpEP (18.3 +/- 7.8 min, P < 0.005). Loss of the L4 SpEP in Group 2 (49.3 +/- 27.8 min) was earlier than in Group 3 (73.7 +/- 26.1 min, P < 0.05). Early postoperative motor function (modified Tarlov scale) correlated with time from loss of the L4 SpEP until reperfusion of the distal aorta (r = 0.93). The sensitivity, specificity, and accuracy of the L4 SpEP in predicting neurologic dysfunction was 92.8% (13 abnormal/14 predicted), 90.9% (20/22), and 91.7% (33/36).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2006

Emergence of physiological rhythmicity in term and preterm neonates in a neonatal intensive care unit.

BACKGROUND: Biological rhythmicity, particularly circadian rhythmicity, is considered to be a key mechanism in the maintenance of physiological function. Very little is known, however, about biological rhythmicity pattern in preterm and term neonates in neonatal intensive care units (NICU). In this study, we investigated whether term and preterm neonates admitted to NICU exhibit biological rhythmicity during the neonatal period. METHODS: Twenty-four-hour continuous recording of four physiological variables (heart rate: HR recorded by electrocardiogram; pulse rate: PR recorded by pulse oxymetry; respiratory rate: RR; and oxygen saturation of pulse oxymetry: SpO2) was conducted on 187 neonates in NICU during 0-21 days of postnatal age (PNA). Rhythmicity was analyzed by spectral analysis (SPSS procedure Spectra). The Fisher test was performed to test the statistical significance of the cycles. The cycle with the largest peak of the periodogram intensities was determined as dominant cycle and confirmed by Fourier analysis. The amplitudes and amplitude indexes for each dominant cycle were calculated. RESULTS: Circadian cycles were observed among 23.8% neonates in HR, 20% in PR, 27.8% in RR and 16% in SpO2 in 0-3 days of PNA. Percentages of circadian cycles were the highest (40%) at < 28 wks of gestational age (GA), decreasing with GA, and the lowest (14.3%) at > or = 37 wks GA within 3 days of PNA in PR and were decreased in the later PNA. An increase of the amplitude with GA was observed in PR, and significant group differences were present in all periods. Amplitudes and amplitude indexes were positively correlated with postconceptional age (PCA) in PR (p < 0.001). Among clinical parameters, oxygen administration showed significant association (p < 0.05) with circadian rhythms of PR in the first 3 days of life. CONCLUSION: Whereas circadian rhythmicity in neonates may result from maternal influence, the increase of amplitude indexes in PR with PCA may be related to physiological maturity. Further studies are needed to elucidate the effect of oxygenation on physiological rhythmicity in neonates.

Journal Article↗

PubMed2003

Correlation between heart rate and performance during Olympic windsurfing competition.

The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal oxygen consumption (.VO(2max)) trial and national windsurf competitions wearing a HR monitor. One hundred and forty-three individual races were examined. Racing HR was expressed as a percentage of (1) HR(max) (maximal treadmill HR) and (2) HR(reserve) (HR(max)-HR(rest)). The performance (racing classification: RC, which is inversely proportional to performance) was significantly correlated to the racing HR response in both light wind (LW): LW-RC=-0.12(%HR(reserve))+13.03; r=-0.71, r(2)=0.50, p<0.001, and medium wind (MW): MW-RC=-0.11(%HR(reserve))+10.99; r=-0.66, r(2)=0.43, p<0.001. The results showed similar correlations between performance and %HR(max). Post racing lactate concentration was higher in LW compared to MW [7.14 (0.21) and 5.18 (2.02) mmol.l(-1), respectively]. There was a negative correlation between the highest racing HR (%HR(reserve)) of each athlete and the second ventilatory threshold expressed as a percentage of .VO(2max) ( r=-0.71, p<0.05). To summarize, this study showed that light and medium wind Olympic windsurfing performances are highly dependent on the capacity of the athlete to maintain a high HR for long periods of time. Furthermore, windsurfing is highly dependent on the athlete's physical fitness level as shown by the correlations between racing HRs and laboratory physiological variables.

Adult↗

PubMed1993

Symptomatic hyponatremia during prolonged exercise in heat.

Although hyponatremia (HN) has been reported among endurance athletes, its etiology often remains uncertain and of great interest to clinicians and physiologists. This case report presents physiologic evidence regarding the etiology and development of HN during exercise in the heat. A 21-yr-old male volunteer (K.G.) unexpectedly experienced symptomatic HN during a research investigation that involved controlled sodium (Na+) intake (137 mEq Na+.d-1 for 7d) and exercise-heat acclimation (41 degrees C; 30 min.h-1, 8 h.d-1 for 10 d). Fluid balance, physiologic variables, and hematologic/hormone data were measured before and after the HN episode, with similar measurements recorded for nine unaffected volunteers. The results indicated: 1) HN was verified in K.G. (plasma Na+ < 130 mEq.l-1) after only 4 h of mild, intermittent exercise in heat; 2) K.G.'s heart rate, rectal temperature, blood pressure, and Na+ losses in sweat and urine were < or = control subjects at all times; 3) between hours 4-7, an inappropriately large release of vasopressin coincided with a decrease of urine volume to 0 ml.h-1. It was concluded that a large intake (10.3 l.7h-1) and retention (2.77 l.7h-1) of water and a "low normal" initial plasma Na+ (134 mEq.l-1) were primary factors in the development of HN in K.G., whereas Na+ losses in sweat and urine were normal and served only to exacerbate HN.

Adult↗

PubMed1999

Undergraduate students' misconceptions about respiratory physiology.

Approximately 700 undergraduates studying physiology at community colleges, a liberal arts college, and universities were surveyed to determine the prevalence of our misconceptions about respiratory phenomena. A misconception about the changes in breathing frequency and tidal volume (physiological variables whose changes can be directly sensed) that result in increased minute ventilation was found to be present in this population with comparable prevalence (approximately 60%) to that seen in a previous study. Three other misconceptions involving phenomena that cannot be experienced directly and therefore were most likely learned in some educational setting were found to be of varying prevalence. Nearly 90% of the students exhibited a misconception about the relationship between arterial oxygen partial pressure and hemoglobin saturation. Sixty-six percent of the students believed that increasing alveolar oxygen partial pressure leads to a decrease in alveolar carbon dioxide partial pressure. Nearly 33% of the population misunderstood the relationship between metabolism and ventilation. The possible origins of these respiratory misconceptions are discussed and suggestions for how to prevent and/or remediate them are proposed.

Adolescent↗

PubMedDate not supplied

Hardware-software approach for neonatal cardiovascular risk estimation.

Genetic risk is a primary contributing factor to the predisposition of a newborn child to elevated blood pressure later in life. To determine whether there is a correlation between potential genetic risk as established by family history and measured physiologic variables in the neonate, the systolic and diastolic blood pressures and heart rates of 150 newborn babies were automatically monitored at about 30-minute intervals for 48 hours with a Nippon Colin device, starting early after birth. Circadian parameters (obtained by the linear least-squares fit of a 24-hour cosine curve to each individual series) and descriptive statistics for the three circulatory variables were used in a multiple-regression analysis to compute a linear prediction function for a neonatal cardiovascular risk score. This score was obtained for each neonate on the basis of the presence or absence of overt cardiovascular disease, elevated blood pressure, or obesity across two generations, those of the newborn's parents and grandparents. Results from multiple regression indicate that the best model for prediction of the risk score includes the circadian amplitudes of systolic and diastolic blood pressure, the circadian range of heart rate, and the 90% range and standard deviation of diastolic blood pressure. The multiple correlation coefficient between the predicted and the computed risk scales is 0.666, a value that, although statistically significant (p < 0.001), is still low for a generalized practical use of the model in predicting risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular Diseases↗

PubMed1976

A psychophysiological study of determinants for detection of deception.

Three studies were conducted to obtain available data on the determinants for detection of deception rates. (a) Psychophysiological measures were evaluated for effectiveness in detecting deception. A relevant-irrelevant method was used with two conditions; neutral stimulus and personal stimulus. Of the physiological variables, skin potential response, skin resistance response, finger pulse volume, and skin blood flow were significant indicators of deception. (b) Three experiments were conducted to study the psychophysiological effects of false and true feedback of skin potential response on the detection rates. It was concluded that the subjects receiving information that they were detectable were easier to detect than the subjects who believed that they were not detected and the subjects who received feedback of actual responses. (c) With the use of skin potential response channel, significant detection rates were obtained for all experiments under the condition that subjects verbally lied by means of "No" responses. On the other hand, the subjects who were motivated to deceive produced differentially augmented responses in the absence of any verbal response and also when the subjects told the truth to critical items and lied to irrelevant ones.

Adolescent↗

PubMed2007

Noninvasive measurement of intracranial pressure: is it possible?

BACKGROUND: Some publications suggest a strong correlation between the intracranial pressure and the intraocular pressure. Other studies claim no correlation between these two physiologic variables. Our aim was to study whether the tonometry could be a useful method to evaluate intracranial pressure in patients with suspected intracranial abnormality. METHODS: We evaluated the correlation between the intracranial pressure and the intraocular pressure, the intracranial pressure and the mean arterial pressure, and the intraocular pressure and the mean arterial pressure in 22 patients, initially comatose, who were admitted to our hospital. All patients required the intracranial pressure monitoring on clinical grounds. Simultaneous measurements were performed and recorded. RESULTS: We calculated both the linear correlation coefficient and the Spearman rank-order correlation coefficient. We found significant correlation between the intraocular pressure and the mean arterial pressure in 12 patients; however, significant correlation between the intraocular pressure and the intracranial pressure was found in only 2 patients. CONCLUSION: Tonometry is not an appropriate method for the assessment of intracranial pressure increases.

Adult↗

PubMed2006

Effect of transdermal nicotine administration on exercise endurance in men.

Nicotine is widely reported to increase alertness, improve co-ordination and enhance cognitive performance; however, to our knowledge there have been no attempts to replicate these findings in relation to exercise endurance. The purpose of this study was to determine the effects nicotine might have on cycling endurance, perception of exertion and a range of physiological variables. With local ethics committee approval and having obtained informed consent, 12 healthy, non-smoking men (22 +/- 3 years; maximal O2 uptake, 56 +/- 6 ml kg(-1) min(-1), mean +/- s.d.) cycled to exhaustion at 18 degrees C and 65% of their peak aerobic power, wearing either a 7 mg transdermal nicotine patch (NIC) or a colour-matched placebo (PLA) in a randomized cross-over design; water was available ad libitum. Subjects were exercising at approximately 75% of their maximal O2 uptake with no differences in cadence between trials. Ten out of 12 subjects cycled for longer with NIC administration, and this resulted in a significant 17 +/- 7% improvement in performance (P < 0.05). No differences were observed for perceived exertion, heart rate or ventilation. There were no differences in concentrations of plasma glucose, lactate or circulating fatty acids. In the absence of any effect on peripheral markers, we conclude that nicotine prolongs endurance by a central mechanism. Possible modes of action are suggested.

Adaptation, Physiological↗

PubMed1989

Sensation seeking and auditory evoked potentials.

The relationship between auditory evoked potentials (AEP) and the German version of Zuckerman's Sensation Seeking Scale was examined. The slope of the amplitude/stimulus intensity function (N1/P2 component) and the N1 latency were particularly studied, as these variables have been found to be potential predictors of the response to lithium prophylaxis. Thirty-three healthy subjects participated in two testing series on the first day and in a third run 3 weeks later. Binaural clicks at four intensity levels (58, 68, 78, 88 dB HL, ISI 2.1 sec) were presented in randomized order by headphone. Eighty responses were averaged at each intensity level. The pattern of correlation between the German version of the Sensation Seeking Scale and a personality inventory (FPI) supports the validity of the Sensation Seeking Scale. Only a tendency toward steeper slopes of the amplitude/stimulus intensity function (ASF) in high sensation seekers was observed in the first run. However, there was a significant interaction of sensation seeking and the test run. Only high sensation seekers showed an influence of retesting on the slope of the ASF, leading to a decrease of the slope in the second, compared with the first run. This might correspond to the psychological pattern of sensation seeking, which is characterized by a permanent need for new and exciting situations and, at the same time, by a rapid loss of interest in these situations. With regard to the N1 latency, a significant interaction of sensation seeking and lead was found. Low sensation seekers showed longer N1 latencies over the right than over the left hemisphere, a finding that accords with some psychophysiological theories on the relation between asymmetric hemispherical activation and certain psychological constructs. Our results support the view that sensation seeking is a personality feature that is closely related to certain physiological variables.

Adult↗

PubMed1992

[Are mercury sphygmomanometers obsolete?].

The measurement of blood pressure during medical visits is limited in its diagnostic, prognostic and therapeutic value by physiologic variability of hypertension and measurement errors. Repeated measurements reduce the effect of spontaneous variations of blood pressure. They allow a more secure assessment of real tension. Regular training for proper technique and elimination of arbitrary preference for rounded last digits or automated recording minimize erroneous measurements. By the multitude of recorded parameters the ambulatory measurement over 24 hours and the self-assessment of blood pressure provide a representative diurnal profile superior to individual measurements at the doctors office. Each of the two methods has its own field of application, although prognostic and therapeutic aims seem similar. The continuous recording over 24 hours is suited for initial assessment and identification of hypertensive patients. Self-assessment of blood pressure has its use for long-term follow up and optimization of therapy. Both methods are complementary and only limited from wider use by lacking internationally accepted normal values and standardization of available devices.

Blood Pressure↗

PubMed1991

Polysomnography at a sleep disorders unit in Melbourne.

OBJECTIVE: To outline the procedure of polysomnography as carried out in a sleep disorders unit in Melbourne and to describe the patients undergoing polysomnography in terms of their age and sex and the sleep disorder diagnosed. DESIGN: A retrospective survey of consecutive patients who required diagnostic polysomnography. SETTING: The Sleep Disorders Unit at Epworth Hospital, a large private hospital in Melbourne. PATIENTS: Two hundred consecutive patients who underwent polysomnography over a seven-month period. Their ages ranged from 19 to 77 years. INTERVENTIONS: All patients had diagnostic polysomnography for one night in the sleep laboratory. This involved 12 to 14 physiological variables being monitored continuously overnight by means of a new digital recording and sleep analysis system. MAIN OUTCOME MEASURES: Patients were categorised according to their main sleep disorder or primary diagnosis. Additional sleep disorders in some patients were categorised as secondary diagnoses. RESULTS: The commonest age group among both male and female patients was 40-49 years. Overall, men outnumbered women three to one. Almost two-thirds of all patients had as their primary diagnosis some degree of obstructive sleep apnoea syndrome or simple snoring. The next most common diagnosis was periodic limb movement disorder. The remaining diagnoses included a variety of sleep disorders, from narcolepsy to sleep terrors. CONCLUSIONS: Despite its complexity and time-consuming nature, polysomnography is an essential procedure for the diagnosis and treatment of a wide range of sleep disorders. More sleep laboratories and a greater emphasis on the multidisciplinary teaching of sleep disorders medicine will be required in Australia.

Adult↗

PubMed1976

The effect of repeated phlebotomy on bilirubin turnover, bilirubin clearance and unconjugated hyperbilirubinaemia in the Crigler-Najjar syndrome and the jaundiced Gunn rat: application of computers to experimental design.

1. A multicompartmental model of erythrokinetics and bilirubin production has been developed to predict the consequences of chronic phlebotomy on daily bilirubin turnover. 2. Control values for four physiological variables including bilirubin turnover were determined in a 20-year-old woman with type I congenital nonhaemolytic jaundice (Crigler-Najjar syndrome). With these base-line data, the model predicted the following changes during phlebotomy: a 34% fall in bilirubin turnover; a 240% increase in the haemoglobin content of bone-marrow erythroid precursors; a 25% fall in the half-life of 51Cr-labelled erythrocytes; a characteristic alteration of the erythrocyte survival curve after labelling with [2-14C]glycine. 3. On the assumption, previously validated in normal volunteer subjects and patients with Gilbert's syndrome, that hepatic bilirubin clearance was independent of turnover and would therefore remain unchanged, a fall in plasma unconjugated bilirubin concentration during phlebotomy from 436 to 282 mumol/1 was expected. 4. Accordingly, the patient underwent phlebotomy 350 ml/week for 2 months, and 500 ml/week during an additional 3 months. Appropriate studies during phlebotomy confirmed each of the predictions in paragraph 2 above. In particular, turnover fell by 31%. Unexpectedly, plasma unconjugated bilirubin remained essentially unchanged. Analogous results were observed in phlebotomized jaundiced Gunn rats. 5. Kinetic studies in both the patient and the rats demonstrated that the failure of plasma unconjugated bilirubin to fall in parallel with bilirubin turnover resulted from a prolongation of the terminal half-life of radioactively labelled bilirubin and a fall in bilirubin clearance in every instance. 6. These studies indicate that (a) in congenital non-haemolytic jaundice, bilirubin clearance is uniquely influenced by bilirubin turnover and (b) compartmental modelling and kinetic studies are useful for predicting and interpreting the results of both physiological experiments and experimental therapeutic regimens.

Adult↗

PubMed1992

Free plasma catecholamine levels in healthy subjects: a basal and dynamic study. The influence of age.

We studied the levels of free plasma noradrenaline (norepinephrine, NE), adrenaline (epinephrine, E), and dopamine (DA) in 143 normal subjects, either basally or, in a part of them, in response to four tests stimulating the sympathoadrenomedullary activity: the tilt-table test (TTT), the cold-pressor test (CPT), the mental-arithmetic test (MAT), and the insulin tolerance test (ITT). In both cases we evaluated the influence of age, which is considered the main physiological variable affecting the peripheral sympathetic activity. A normal distribution of values was observed, in the basal study, only for NE, while E and particularly, DA levels were distributed in an non-homogeneous fashion; a direct correlation was observed between age of subjects and NE levels, while neither E, nor DA levels showed any correlation with the aging process; sex did not influence any of the catecholamines. In the dynamic study, CPT, ITT and, above all, TTT elicited a significant rise in NE levels, while the E release was greatly stimulated by the insulin-induced hypoglycaemia. Neither NE, nor E levels rose after the MAT stimulation. Also in this case, the elderly showed an increased noradrenergic responsiveness when compared with the young subjects, confirming the existence of an 'up-regulation' of the peripheral sympathetic tone in old people.

Adolescent↗

PubMed2006

Intersession reproducibility of retinal nerve fiber layer thickness measurements by GDx-VCC in healthy and glaucomatous eyes.

BACKGROUND: To assess intersession reproducibility of retinal nerve fiber layer (RNFL) thickness measurements on scanning laser polarimetry with variable corneal compensation (GDx-VCC) in a sample of healthy subjects and glaucoma patients. METHODS: One eye each from 29 healthy and 29 glaucomatous subjects was selected and underwent RNFL scanning by the same operator at baseline and 1 week later. Glaucoma diagnosis relied on the presence of a reproducible defect on automated perimetry. GDx-VCC parameters considered were those available on page 1 of the printout [TSNIT average and standard deviation (SD), superior and inferior average (SA, IA), Nerve Fiber Indicator]. Reproducibility was assessed by calculating coefficient of variation and intraclass correlation coefficient separately for the two groups and for each parameter. The percentage of eyes with an intersession difference in thickness parameters of more than 5% was also calculated. RESULTS: Coefficient of variation was <6% for TSNIT average, SA and IA in both groups. Corresponding values for TSNIT SD in healthy subjects and in glaucoma patients were 13.7 and 11.4%, respectively, whereas for Nerve Fiber Indicator they were 82.9 and 13.3%. Intraclass correlation coefficient ranged from 0.794 to 0.907 in healthy subjects and from 0.924 to 0.972 in glaucoma patients. In healthy subjects, TSNIT average, SA and IA intersession difference was 5% or less in 55-69% of eyes, whereas the value for TSNIT SD was 34.5%. Corresponding values in glaucomatous eyes ranged from 69 to 79.3% for TSNIT average, SA and IA and was 37.9% for TSNIT SD. CONCLUSIONS: Intersession reproducibility of RNFL thickness measurements on GDx-VCC is high, both in healthy and in glaucomatous eyes. In a few cases, however, intersession variation may be larger than 10%. Caution is necessary while interpreting these changes during follow-up, in order to separate physiological variability from real RNFL thickness variations.

Aged↗

PubMedDate not supplied

Physiologic measures of kangaroo versus incubator care in a tertiary-level nursery.

OBJECTIVE: To determine the safety and feasibility of kangaroo care in a tertiary-level nursery as defined by apnea, bradycardia, and oxygen desaturation. DESIGN: Prospective, long-term, repeated measures with a convenience sample. SETTING: A 20-bed, tertiary-level nursery with approximately 400 admissions a year. PARTICIPANTS: Eight mother-infant pairs. INTERVENTIONS: Researchers compared incubator care with kangaroo care for 4 hours a day, 6 days a week, for 3 weeks. Physiologic variables were monitored daily and recorded continuously on a polygraph for 8 hours each week. MAIN OUTCOME MEASURES: Amount of apnea, bradycardia, and oxygen desaturation. SECONDARY OUTCOME MEASURES: Heart rate, respiratory rate, percent sleep time, and skin temperature. RESULTS: Apnea, bradycardia, oxygen saturation, heart rate, and respiratory rate were similar during both kangaroo (K) and incubator (I) care. The infants experienced a lower percent (mean +/- standard deviation, K versus I) of total sleep (47 +/- 15 versus 64 +/- 19, p < .003) during kangaroo care. The infants' mean +/- standard deviation temperature during the kangaroo care (36.5 degrees C +/- 0.64 degrees C) was lower (p < .03) than that of the control periods before (36.8 degrees C +/- 0.27 degrees C) or after (36.7 degrees C +/- 0.26 degrees C). Percent sleep time and skin temperature were slightly lower during kangaroo care, but the differences were not clinically significant. CONCLUSION: Kangaroo care is safe and feasible for selected mothers and infants in a tertiary-level nursery.

Adult↗

PubMed2002

Attenuated carbohydrate and gill Na+, K+ -ATPase stress responses in whitefish caged near bleached kraft mill discharges.

Exposure to biologically treated bleached kraft mill effluent (BKME) is demonstrated to greatly modify the acute physiological stress response in fish and, accordingly, to lead to inconsistencies in data interpretation due to dissimilar effects of handling procedures on reference and exposed fish. To consider this phenomenon, juvenile whitefish (Coregonus lavaretus) were caged for 30 days in four reference sites and in three areas influenced by different BKME discharges. After exposure, fish were subjected to the impacts of low-level handling by raising the cages to the water surface, serially handnetting the fish, and transferring ( approximately 10 min) the submerged cages to the research vessel. The data on physiological variables were pooled within each area to three groups according to the periods (<4 min, 10-20 min, 21-40 min) from the onset of handling to the sampling of individual fish. BKME-exposed whitefish sampled during the first period exhibited lower plasma cortisol and blood lactate levels and higher red blood cell Na+ concentrations than reference fish sampled during the same period. In reference whitefish, along with increased plasma cortisol and blood lactate levels, gill ATPase activity as well as liver glycogen and blood glucose levels were markedly affected by the handling procedure, while the latter three responses were strongly attenuated in exposed whitefish. Red blood cell Na+ and K+ and blood hemoglobin responses vanished in only one mill area. These findings, in accordance with similar results of earlier studies dealing with the same species, point to the need for this kind of time-dependent approach to achieve reliable and comparable outcomes in field experiments and encourage work on determining the importance of functional deviations noted in fish exposed to anthropogenically modified water qualities.

Adaptation, Physiological↗