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Results for “physiologic variables”

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PubMed1988

Outcome prediction in critically ill patients by means of oxygen consumption index and simplified acute physiology score.

Both oxygen consumption index (VO2-index) and simplified acute physiology score (SAPS) are reported to be reliable predictors of the ultimate outcome in critically ill patients. The purpose of this study was to verify whether survivors and nonsurvivors have different VO2-indices and whether the prognostic potency of SAPS can be improved by addition of VO2-index as a supplemental physiological variable. In 50 mechanically ventilated surgical ICU patients with heterogeneous underlying diseases, SAPS was calculated and VO2-index was determined by continuous 24-h measurement of oxygen consumption. The VO2-indices of survivors and nonsurvivors were not significantly different (p greater than 0.05), which is in contrast to the results of earlier studies. This contrast may be explained by a difference both in methods of VO2-measurement and in study populations. SAPS was significantly lower in survivors than in nonsurvivors (p less than 0.005) and was able to classify the patients correctly into groups of increasing probability of death. However, SAPS failed to be a helpful prognosticator in the individual patient. The addition of VO2-index to SAPS as a supplemental physiological variable did not substantially improve the prognostic potency. Because a higher VO2-index did not necessarily indicate a better survival chance, there is no argument for therapeutic interventions aimed exclusively at increasing VO2-index, as suggested previously.

Adolescent↗

PubMed1986

The effects of an arm ergometer training programme on wheelchair subjects.

The purpose of the present investigation was to study the effects of an arm ergometer training programme on several physiological variables of recreational wheelchair subjects. Ten paraplegics (5 experimental, 5 control) were tested prior to and immediately after a 2 month exercise regimen at 80% of peak heart rate (30 min per day, 5 days per week, for 8 consecutive weeks at 50 rev/min). The results demonstrated significant increases (P less than 0.05) in VO2max (1 min-1 & ml kg-1 min-1) and workload but only mild improvements in maximal heart rate and post exercise blood lactates. Body fat, vital capacity and forced expiratory volume did not change with training. Triceps lateralis fibre distribution and fast twitch (FT) fibre area were unaffected by the endurance training programme. However, slow twitch (ST) fibre area increased (P less than 0.05) with training. The results indicate that physiological variables of paraplegic subjects following an arm ergometer endurance training programme react similarly to changes previously observed in non-handicapped subjects. The values when compared with normals are low as a result of the relative inactivity of the subjects due to the lack of available exercise programmes for wheelchair people.

Adolescent↗

PubMed2005

Mercaptoethylguanidine inhibition of inducible nitric oxide synthase and cyclooxygenase-2 expressions induced in rats after fluid-percussion brain injury.

The present study examined the temporal expression of nitric oxide synthase (iNOS) and cyclo-oxygenase (COX)-2 in rat brains after traumatic brain injury (TBI). We studied the effects of mercaptoethylguanidine (MEG), a dual inhibitor of the inducible iNOS and COX with scavenging effect on peroxynitrite, on physiologic variables, brain pathogenesis, and neurologic performance in rats after a lateral fluid percussive-induced TBI. Mean arterial blood pressure and percentage cerebral tissue perfusion in MEG-treated TBI rats showed significant improvement when compared with TBI rats. Immunohistochemical analysis showed a marked number of iNOS and COX-2 immunopositive cells in the cerebral cortex ipsilateral to the injury in TBI rats when compared with MEG-treated TBI rats. MEG also significantly decreased the number of hyperchromatic and shrunken cortical neurons when compared with TBI rats' brain nitrate/nitrite, and prostaglandin E2 levels were attenuated in MEG-treated TBI rats when compared with TBI rats. It is therefore suggested that treatment of MEG via inhibition of iNOS and COX-2 might contribute to improved physiologic variables, neuronal cell survival, and neurologic outcome after TBI.

Animals↗

PubMed1993

Acute effects of the heavy metal antidotes DMPS and DMSA on circulation, respiration, and blood homoeostasis in dogs.

The heavy metal antidotes sodium-2,3-dimercaptopropane-1-sulfonate (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) were investigated in anaesthetized dogs for their effects on a variety of physiological variables and parameters. In addition, the influence of both dithiols on oxygen consumption and ferrihaemoglobin production was studied in blood and red blood cells in vitro. DMPS (15 and 75 mg/kg i.v.) did not affect respiration, central venous pressure, left ventricular pressure or cardiac output and showed only marginal, statistically non-significant effects on aortic and effective perfusion pressure. In contrast to the slight, non-significant changes due to DMPS (15 mg/kg i.v.), an equimolar dose of DMSA (12 mg/kg i.v.) led to a slight transient decrease in femoral blood pressure with strong reflex tachycardia and increase in blood flow. The higher DMPS dose (75 mg/kg i.v.), however, caused marked decreases in femoral blood pressure and blood flow, strong changes in blood gases and pH, and lactacidosis. Most of the physiological variables and parameters did not return to the initial level by 60 min. The R-spike of the electrocardiogram decreased, and the T-wave increased. Experiments on the denervated hind leg indicate that DMPS may be a direct vasodilator. The fall of blood pressure due to DMPS was markedly reduced when 30% ferrihaemoglobin had been formed by 4-dimethylaminophenol.HCl (DMAP). The highest DMPS dose (150 mg/kg i.v.) provoked circulatory failure and respiratory arrest. Artificial ventilation with room air restored spontaneous respiration, but one of three animals did not survive this dose for more than 90 min. DMPS and DMSA reacted with oxygen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2001

The use of dGPS and simultaneous metabolic measurements during orienteering.

PURPOSE: The Global Positioning System (GPS) is a satellite-based system for navigation. With this system, it is possible to pinpoint a subject's location on earth and to display the speed of movement. With the use of differentiation (dGPS), the accuracy of the GPS position and speed measurements can be improved. Our purpose was to investigate whether it would be possible to relate dGPS data with physiological variables in a field test and thus achieve a more controlled field test and hence improve the value of sport-specific testing. METHODS: 10 male orienteers were equipped with a portable metabolic gas analyzer and a differential Global Positioning System (dGPS). A field test was performed on a 4.3-km orienteering course. Oxygen uptake, carbon dioxide excretion, and heart rate were determined every 10 s. Speed was calculated by Doppler shift every 2 s and by differences in dGPS time and position. Validation of dGPS position, distance, and speed measurements was made on two fixed positions and on a 115-m straight asphalt road. RESULTS: The orienteers' route was visualized by the dGPS equipment. Detailed analysis of running speed in different sections of the course was made possible. Further, it was possible to relate each physiological data to the location of the subject. The correlation coefficient between speed measured by dGPS and speed measured by chronometry was r = 0.9995-0.9996. The mean errors of distance and position measurements were 0.04-0.7% and 1.94-2.13 m, respectively. CONCLUSION: dGPS was shown to be a method that could give detailed information about a subject's speed and position. It was further demonstrated that physiological variables could be related to dGPS data.

Acceleration↗

PubMed1995

Skin blood flow changes during routine nursery procedures.

OBJECTIVE: The objective of this study was to establish that changes in skin blood flow could serve as an index of pain and discomfort in newborn infants. METHODS: Skin blood flow changes during intensive care procedures and during morphine administration were measured in a group of newborn infants using a laser Doppler technique. Heart rate, respiratory rate and oxygen saturation were also measured. Changes in skin blood flow and physiologic variables that occurred during procedures were analyzed and compared among procedures. RESULTS: Measurements were made during 145 procedures in 15 infants 2-32 days old with birth weights of 500-2900 g and gestational ages of 23-37 weeks. Ten of the infants were receiving mechanical ventilation. Skin blood flow increased 27-134% during lancet puncture of the heel, physical handling, standard suctioning and chest physiotherapy, and there were no changes during closed system suctioning. Skin blood flow decreased 35% by 20 min after intravenous morphine. Changes seen in heart rate, respiratory rate and oxygen saturation were generally minimal. CONCLUSIONS: We conclude that laser Doppler skin blood flow changes could be an index of neonatal pain and discomfort; even noninvasive handling procedures are associated with increases in skin blood flow; and changes in skin blood flow may be more useful than conventional physiologic variables in assessing the response to intensive care nursery procedure.

Analgesics↗

PubMed2004

Regulation of renal adenosine excretion in humans--role of sodium and fluid homeostasis.

BACKGROUND: Adenosine is a vasoactive metabolite of ATP hydrolysis that is involved in the regulation of renal haemodynamics, tubular reabsorption and renin release. Elevated tissue levels are found under conditions of increased metabolic load, ischaemia or renal injury. Urinary adenosine excretion (EADO) may therefore provide a sensitive marker of renal functional impairment in allograft rejection and kidney disease. To provide a basis for evaluation of EADO in clinical settings, we investigated, in an intra-individual, crossover clinical trial the physiological variability and regulation of EADO in response to altered sodium and fluid balance. METHODS: Twelve healthy volunteers were randomized to normal (ad libitum), low (<5 g/day) or high (supplementation of 100 mg/kg/day) sodium chloride diets for 8 days prior to assessment of renal haemodynamics and tubular function in standard clearance investigations. Following baseline periods, fluid homeostasis was altered independently by acute oral water load. EADO was determined in 24 h urine collections and during clearance investigations. RESULTS: Mean EADO in humans was 3.2+/-0.2 micromol/ 24 h during euvolaemia and normal sodium intake. A weak correlation was found between sodium load and EADO. In clearance experiments, variation in EADO was <1.3-fold, despite profound alterations in sodium intake. EADO was independent of urinary flow rate. Renal haemodynamics were not significantly altered by dietary regimen or by acute volume load. CONCLUSION: In summary, the physiological variability of EADO is remarkably small in humans. We demonstrate that even profound alterations in sodium and fluid homeostasis do not significantly affect EADO. These data provide a basis for evaluation of elevated EADO as a marker of renal injury in various clinical settings.

Adenosine↗

PubMedDate not supplied

A system for integrated measurement of ventilator settings, lung volume change and blood gases during high-frequency oscillatory ventilation.

To describe and validate a system for integrated measurement of ventilator settings and dependent physiological variables during high-frequency oscillatory ventilation (HFOV). A custom interface was built for data acquisition. Lung volume change was determined by respirator inductive plethysmography (RIP), modified to sampling rates of 140 Hz. Blood gas analysis was obtained using a continuous intra-arterial blood gas monitoring system. FIO2 was measured by means of an electrochemical sensor. Pressure at the airway opening and trachea (microtip transducer) were sampled. The data acquired were sent to a laptop computer for analysis, display and storage. The system was tested during a lung recruitment procedure in an animal model of respiratory distress. Linearity of the RIP was checked by gas volume injection using a supersyringe. The system operated successfully. Agreement between RIP-measured volume with injected volume was excellent; bias was 5 ml; limits of agreement were 1-9 ml. Graphs were obtained, showing the relationship between imposed mean airway pressure and lung volume change, and oxygenation. The integration of ventilator settings and dependent physiological variables may provide useful information for clinical, instructional and research application.

Animals↗

PubMedDate not supplied

Chronic orthostatic and antiorthostatic restraint induce neuroendocrine, immune and neurophysiologial disorders in rats.

The tail-cast suspension rat model has been developed in ground laboratories interested in space physiology for extensive study of mechanisms causing the pathophysiological syndrome associated with space flights. We used individually-caged male rats to explore the effects of acute and chronic (7d) orthostatic restraint (OR) and head-down anti-orthostatic restraint (AOR) on a series of physiological variables. The acute restraint study showed that (1) the installation of the OR device induced an acute reaction for 2 days, with a substantial rise in ACTH (x2) and CORT (x6), and that (2) the head-down tilt from OR to AOR induced (i) within 10 min and lasting 60 min a 2-fold rise in the intra-cerebro-ventricular pressure (Picv) monitored with an icv telemetric recording system, which receded to normal between 60 and 120 min; and (ii) within 30 min a short-lived 4-fold rise in plasma ACTH and CORT levels. Chronic OR induced (1) the suppression of the diurnal ACTH/CORT rhythm, with increased mean levels, especially for ACTH, (2) a degraded circadian locomotor activity rhythm manifested by a significant reduction in the spectral power of the 24h periodicity and a concomitant emergence of shorter (ultradian) periodicities, (3) an associated, but less pronounced alteration of the diurnal rhythm in body temperature; and (4) a marked increase in baseline plasma levels of IL-1 beta and an increased reactivity in cytokine release following an E. coli endotoxin (LPS) challenge. AOR induced (1) a similar obliteration of the circadian ACTH/CORT rhythm, (2) the loss of close correlation between ACTH and CORT, (3) a generalized increase in baseline plasma IL-1 beta levels and (4) more extensive degradation of the circadian periodicity for both locomotor activity and, to a lesser extent, body temperature, replaced by dominant spectral powers for ultradian periodicities (3 to 10h). In conclusion, both experimental paradigms--but AOR more than OR--caused a blockade of the circadian rhythmicity of major physiological variables, the loss of normal correlations between ACTH and CORT, and inflammatory-immune hyperreactivity. These pathophysiological disorders may all be parts of a complex chronic stress syndrome.

Adrenocorticotropic Hormone↗

PubMed2005

Menstrual cycle and sex affect hemodynamic responses to combined orthostatic and heat stress.

Women have decreased orthostatic tolerance compared with men, and anecdotal evidence suggests women are more susceptible to orthostatic intolerance in warm environments. Because estrogen and progesterone affect numerous physiological variables that may alter orthostatic tolerance, the purpose of our study was to compare orthostatic tolerance across the menstrual cycle phases in women during combined orthostatic and heat stress and to compare these data with those of men. Eight normally menstruating women and eight males (22 +/- 4.0 and 23 +/- 3.5 yr, respectively) completed the protocol. Women were studied during their early follicular (EF), ovulatory (OV), and midluteal (ML) phases. Men were studied twice within 2-4 wk. Heart rate, cardiac output, blood pressure, core temperature (T(c)), and cutaneous vascular conductance (CVC) were measured during three head-up tilt tests, consisting of two tilts in the thermoneutral condition and one tilt after a 0.5 degrees C rise in T(c). There was no difference in orthostatic tolerance across the menstrual cycle phases, despite higher CVC in the ML phase after heating (EF, 42.3 +/- 4.8; OV, 40.1 +/- 3.7; ML, 57.5 +/- 4.5; P < 0.05). Orthostatic tolerance in the heat was greater in men than women (P < 0.05). These data suggest that although many physiological variables associated with blood pressure regulation fluctuate during the menstrual cycle, orthostatic tolerance in the heat remains unchanged. Additionally, our data support a clear sex difference in orthostatic tolerance and extend upon previous data to show that the sex difference in the heat is not attributable to fluctuating hormone profiles during the menstrual cycle.

Adult↗

PubMed1992

Physiological response to cycling with both circular and noncircular chainrings.

The purpose of this study was to compare physiological variables of endurance-trained cyclists riding with four different chainring designs: round, Shimano Biopace, and two engineered ellipse designs. The ellipse designated Eng10 had the crank arm oriented 10 degrees forward of the major (i.e. longer) axis. Eighty degrees further forward, along the minor axis, was the crank arm orientation for the second ellipse, Eng90. With the major to minor axis ratio of 22.9 cm/16.8 cm (1.36), both ellipses imposed a crank angular velocity variation of 27% relative to the highest velocity assuming constant chain velocity. Best described as a skewed ellipse (i.e., major and minor axes not perpendicular), the Biopace had a major to minor axis ratio of 1.09 thus giving a crank angular velocity variation of 8%. Eleven male cyclists rode at a high (80% of maximum VO2) and a low (60% of maximum VO2) workrate using each chainring. The study was conducted over four consecutive days with the presentation order of the chainrings randomized. Open circuit spirometry was used to collect continuous respiratory data. Heart rate, blood lactate, and cadence values also were measured. None of the physiological variables including rates of oxygen consumption showed significant differences among the chainrings. Thus, the gross efficiency of cycling was not improved by any of the noncircular chainrings. For cycling events where efficiency is a determinant of performance, the noncircular chainrings do not offer any advantage over round chainrings.

Adult↗

PubMed2004

Emotional activation of obese and normal women due to imagery and food content of verbal stimuli in a memory task.

The aim of this study is to look for correlation between a physiological variable (skin conductance, SCL) and cognitive variables (reaction time, RT and productivity score) obtained in a memory task. Subjects were 17 females, including 7 patients and 10 controls. Patients were recruited among women who went to a clinic for alimentary disorders because of obesity and volunteered for this study; controls were normal women of comparable age without any alimentary problem. Tonic variations of SCL were recorded by a computerized polygraph during the execution of the cognitive task, which consisted of a computerized presentation of frequent, everyday used words evenly divided according to an alimentary/nonalimentary content and to a high/low imagery quality. The acquisition session was followed by an immediate recognition session where subjects were asked to identify the previously presented words among an equal number of similar words not included in the acquisition list. The two session series (acquisition and recognition) were repeated three times to evaluate the learning curve and habituation. This same procedure was separately performed with high imagery alimentary/nonalimentary words and with another list of low imagery alimentary/nonalimentary words. During the recognition tasks, both RT and productivity scores were recorded. A correlation analysis between cognitive and physiological variables was carried out to explore how subjects with different attitudes to food react in cognitive and somatic terms when exposed to verbal stimuli concerning this topic and to neutral verbal stimuli. Results show that obese patients have a different emotional activation in front of these verbal stimuli where both the cognitive activity and the somatic responses are affected by their involvement with the verbal stimuli. On the contrary, the imagery effect does not seem to be influenced by the content and by the idiosyncratic reactions to it of the specific groups of subjects.

Adult↗

PubMed2002

GIGANTEA and SPINDLY genes linked to the clock pathway that controls circadian characteristics of transpiration in Arabidopsis.

Several "clock" genes that regulate the circadian system in Arabidopsis thaliana have been identified. The GIGANTEA (GI) gene has been shown to participate in the circadian system that is linked to overt rhythms in gene expression, leaf movements, hypocotyl elongation, and photoperiodic control of flowering in Arabidopsis. During continuous light (LL), circadian expression patterns in gi-2 mutants show reduced amplitudes and altered period lengths when compared with controls. Rhythms in stomatal function, such as transpiration, have been shown to be endogenous and persist in constant lighting conditions. In order to test for a physiologic variable that might be affected by the circadian clock via the GI gene, we compared circadian characteristics of transpiration between three Arabidopsis mutants (gi-2, spy-4, spy-4/gi-2) and wild-type (WT) controls in synchronized (LD for 2.5d) and free-running (LL for 3d) conditions. Each genotype showed a significant circadian rhythm in LD at p < 0.001, with acrophases located near the middle of the daily 14h L-span, with average amplitudes for WT: 18.9%, gi-2: 16.1%, spy-4: 7.7%, and spy-4/gi-2: 5.3%. On the first day in LL, the circadian amplitude was dramatically reduced to 3.1% for gi-2 compared with WT (11.9%), while amplitudes for spy-4 (6.9%) and spy-4/gi-2 (5.7%) were not significantly changed from LD. The amplitude for gi-2 remained low during days 2 (4.2%) and 3 (2.1%) in LL, while it slowly dampened for the WT (8.6 and 6.6%). The amplitudes for spy-4 (6.6%) and spy-4/gi-2 (5.6%) on day 2 in LL were indistinguishable from the LD span, but finally dampened on day 3 in LL (1.9 and 2.3%, respectively). These data suggest that transpiration is a physiologic variable controlled by a circadian system that involves both the GI and SPY proteins.

Arabidopsis↗

PubMed2005

The prevalence of recordings of the signs of critical conditions and emergency responses in hospital wards--the SOCCER study.

OBJECTIVE: To estimate the prevalence of recordings in case notes of disturbed physiological variables in adult admissions in general hospital wards. DESIGN AND SETTING: Retrospective cross-sectional survey of 3160 admissions in general wards in five hospitals in a 14-day period. MAIN OUTCOME MEASURES: Recordings of 26 potential early signs (ES) and 21 potential late signs (LS) of critical conditions. Eight late signs were classified as Liverpool Hospital Equivalent Calling Signs (LES). RESULTS: 54.7% admissions had at least one recording of early signs, 16.0% late signs and 6.4% LES. When ranked in order of recordings per 100 admissions, the top five ES were SpO(2) 90-95% (193.7), systolic blood pressure (SBP) 80-100 mmHg (85.2), pulse rate 40-49 or 121-140 b/min (32.0), SBP 181-240 mmHg (23.0) and "Other" (22.1) (mainly breathlessness or temperature > 38 degrees C). The top five LS were SpO2 < 90% (31.5), pulse rate < 40 or > 140 /min (6.6), SBP < 80 mmHg (4.2), GCS < or = 8 (3.8) and unresponsiveness to verbal commands (2.4). There were average signs per admission of ES 4.4, LS 0.6 and LES 0.19. Although there were differences in rates of recordings of signs across the five hospitals, the patterns of top 10 most frequent were similar. CONCLUSIONS: There was a high incidence of recordings of disturbed physiological variables in general ward patients. Changes to hospital emergency response systems to include rapidly responding teams to patients with the signs of developing critical conditions should be supported by training programmes for ward staff on the early recognition and management of patients with the warning signs.

Adult↗

PubMed2002

Effects of the spin trap agent disodium- [tert-butylimino)methyl]benzene-1,3-disulfonate N-oxide (generic NXY-059) on intracerebral hemorrhage in a rabbit Large clot embolic stroke model: combination studies with tissue plasminogen activator.

BACKGROUND AND PURPOSE: It has been proposed that the novel spin trap agent disodium-[(tert-butylimino)methyl]benzene-1,3-disulfonate N-oxide (NXY-059) may be useful in the treatment of ischemia and stroke. To date, there is little information concerning the safety of NXY-059 when administered in combination with the only Food and Drug Administration-approved pharmacological agent for the treatment of stroke, the thrombolytic tissue plasminogen activator (tPA). Thus, we determined the effects of NXY-059G, a generic form of NXY-059, on hemorrhage and infarct rate and volume when administered alone or in combination with tPA. In addition, we determined whether NXY-059G affected 2 physiological variables, blood glucose levels and body temperature. METHODS: Male New Zealand White rabbits were embolized by injecting a large blood clot into the middle cerebral artery via a catheter. Five minutes after embolization, NXY-059G (100 mg/kg) was infused intravenously; control rabbits received infusions of saline, the vehicle required to solubilize NXY-059G. In tPA studies, the thrombolytic was administered intravenously starting 60 minutes after embolization (20% bolus injection/80% infusion over 30 minutes). Body temperature and blood glucose levels were measured throughout the study. Postmortem analysis included assessment of hemorrhage and infarct rate, size, and location. RESULTS: In the vehicle control group, the hemorrhage rate after a thromboembolic stroke was 52% (n=23), and this was increased by 67% if tPA was administered (n=15). The rabbits treated with NXY-059G in the absence of tPA had a 79% incidence of hemorrhage (n=19), an increase of 52% over the control group. In the combination drug-treated groups, the NXY-059G/tPA group had a 47% incidence of hemorrhage (n=15). There was a decrease of hemorrhage volume in the NXY-059G+tPA group compared with the other 3 groups included in the study. There was no significant effect of NXY-059G either alone or in combination with tPA on infarct rate or volume. NXY-059G did not significantly alter the physiological variables that were measured. CONCLUSIONS: This study suggests that NXY-059G may affect the integrity of the cerebral vasculature when administered immediately after an embolic stroke, as evidenced by an increase in hemorrhage rate. However, when NXY-059G is administered in combination with tPA, it may improve the safety of tPA by reducing the incidence of tPA-induced hemorrhage. The mechanism(s) involved in the NXY-059G-induced increase in hemorrhage rate and reduction of tPA-induced hemorrhage rate remains to be elucidated.

Animals↗

PubMed1996

Protein synthesis within dendrites: ionic and neurotransmitter modulation of synthesis of particular polypeptides characterized by gel electrophoresis.

This study evaluates whether physiological variables differentially affect the local synthesis of protein constituents of synapses in subcellular fractions containing pinched-off dendrites (synaptodendrosomes). Synaptodendrosomes were pulse-labeled in a medium containing 35S-methionine with 3 or 25 mM KCl and in the presence or absence of 0.5 mM EGTA or 10 microM glutamate. Synaptodendrosomes were then subfractionated to prepare synaptic plasma membranes and synaptic junctional complexes. The protein constituents of the synaptic plasma membrane and synaptic junctional complex fractions that were locally synthesized were identified using SDS-PAGE and two-dimensional gel electrophoresis and the extent of labeling of individual bands was analyzed using a Phosphorimager. Analysis of incorporation into individual bands resolved by SDS-PAGE revealed that depolarizing conditions (25 mM KCl) increased the extent of labeling of different bands to a different extent (ranging from 10-70% increases in labeling). Addition of 0.5 mM EGTA decreased the extent of labeling of the same group of bands in both 3 mM KCl and 25 mM KCl conditions. Addition of 10 microM glutamate reduced incorporation especially in the synaptodendrosomes incubated in 25 mM KCl. Two-dimensional gel electrophoresis analyses revealed that the labeled spots that showed differential labeling under the different conditions did not correspond to the most prominent Coomassie-stained spots. These results indicate that the proteins that are synthesized in synaptodendrosomes and regulated by physiological variables are not amongst the more abundant protein constituents of the fractions. Taken together, these results are consistent with the idea that protein synthesis within dendrites may be regulated by synaptic activity.

Analysis of Variance↗

PubMed1991

Normal fluctuation of physiologic cardiovascular variables during anesthesia and the phenomenon of "smoothing".

With the advent of automated anesthesia record keeping devices, concern has arisen that "abnormal" values will appear in the record and possibly lead to medicolegal compromise. A retrospective review of automated records from a series of anesthesia cases was undertaken to determine if abnormal values do occur, how frequent they are, and whether they cause problems. A total of 14,826 (4,942 each) noninvasive heart rate, systolic, and diastolic blood pressure readings from 118 case printouts generated by a Diatek Arkive Patient Information Management System (63 cases) or a Datascope Datatrac record keeper (55 cases) were recorded. The study sample covered a broad range of surgical operations, anesthetic procedures, and patient ages and medical histories. During these 118 anesthetics, the majority of readings of all three variables fell within normal ranges (defined for this study as 80 to 180 and 50 to 110 mm Hg for systolic and diastolic blood pressures, respectively, and 60 to 140 beats/min for heart rate). During the anesthetics, 3.6% of the systolic pressure readings, 13.25% of the diastolic readings, and 4.25% of the heart rate readings were recorded outside these ranges. No serious intraoperative or postoperative anesthesia complications were associated with these out-of-range readings, nor would they be expected in a sample of this size, since serious anesthetic complications are rare. This preliminary observation of one person's experience may help address the concern associated with allowing high and low blood pressure and heart rate readings to be automatically recorded "unsmoothed." In medicolegal situations, it should also begin to demonstrate that such fluctuations are neither uncommon nor abnormal, and that a true record of these readings should be neither a cause for concern nor an opportunity for medicolegal exploitation.

Adult↗

PubMed2004

Effects of hypoxia on coronary flow reserve as determined by myocardial contrast echocardiography in swine.

BACKGROUND: Time-intensity curves derived from microbubble destruction/refilling sequences and recorded using myocardial contrast echocardiography (MCE) can provide parameters that correlate with coronary blood flow. The response of these parameters to adenosine vasodilatation correlates with coronary flow reserve (CFR) measured by fluorescent microsphere techniques (FMT). Currently, no data exist regarding the effect of physiological variables, such as hypoxia, on the determination of CFR by MCE. The purpose of this study was to define the effects of decreases in blood partial pressure of oxygen (PO2) on CFR as measured by MCE. METHODS: Studies were performed in 9 closed chest swine. Low-energy, real-time MCE was performed with commercial instruments in short axis view at papillary muscle level while infusing BR1 at 30 ml/h. High-energy ultrasound bursts (referred to as FLASH frames) destroyed the bubbles every 15 cardiac cycles, and resultant time-intensity curves derived from these sequences were fitted to the exponential function y = A [1-e(-bt)] + c, from which the rate of signal rise (b) was obtained. CFR was calculated as the ratio of b values after adenosine infusion to baseline and was obtained during the control period and after decreasing blood PO2 by giving nitrogen via a respirator to create artificial hypoxic conditions. CFR was independently determined by FMT. RESULTS: Nitrogen led to significant decreases in mean PO2, from (120.6 +/- 18.9) mmHg to (51.8 +/- 15.9) mmHg (P < 0.01). Adenosine produced a similar increase in CFR (2.5 fold vs 3.1 fold) as assessed by MCE and FMT during the control period. The decrease in PO2 post nitrogen resulted in a slight increase in values at rest: 0.46 +/- 0.15 to 0.53 +/- 0.18 for b and (1.39 +/- 0.66) ml x min(-1) x g(-1) to (1.72 +/- 0.30) ml x min(-1) x g(-1) for myocardial blood flow (MBF) (both P < 0.05). In addition, values decreased in response to adenosine using both techniques: 1.05 +/- 0.35 to 0.82 +/- 0.27 for b and (4.30 +/- 3.16) ml x min(-1) x g(-1) to (3.93 +/- 1.27) ml x min(-1) x g(-1) for MBF (both P < 0.05). Thus, CFR was markedly reduced under hypoxic conditions, to 1.4 by MCE (P < 0.05 compared with the baseline), and to 2.5 by FMT (P > 0.05 compared with the baseline). CONCLUSIONS: CFR values diminish under hypoxic conditions according to both MCE and FMT. The reductions in CFR involve both an increase in resting values and a decrease in post adenosine measurements, as determined by both techniques. The reduction in CFR under hypoxia is slightly greater using MCE than using FMT. Physiological variables, such as hypoxia, must be taken into consideration when assessing CFR by MCE.

Adenosine↗