Group Mean Data Research Articles

Cardiorespiratory Adaptations to a Heart Rate Based High Intensity Parallel Squat Resistance Training Program

Typical resistance training (RT) does not result in improvements in peak oxygen consumption (VO2peak) in young adults. PURPOSE: To investigate the effects of a 12-week parallel squat resistance training program utilizing aerobic training principles and heart rate training ranges on VO2peak. METHODS: The RT program was designed to comply with ACSM minimal guidelines for increasing cardiorespiratory fitness. Young adult males (n=9) performed parallel squats 3 times per week on non-consecutive days. Each training session consisted of 10 sets of parallel squats with rest periods being determined by HR. The sets were performed as follows: Set 1 = 20 repetitions (reps) at 20% one repetition maximum (1RM); set 2 = 20 reps at 25% 1RM; set 3 = 20 reps at 25% 1RM; set 4 = 20 reps at 30% 1RM; set 5 = 20 reps at 35% 1RM; set 6 = 18 reps at 50% 1RM; set 7 = 15 reps at 65% 1RM; set 8 = 12 reps at 70% 1RM; set 9 = 10 reps at 75% 1RM; set 10 = 8 reps at 80% 1RM. Heart rate was maintained at 55–75% of maximal HR during all training sessions, and sessions lasted 20–30 minutes. Pre- and post training testing included a 1RM parallel squat, an incremental cycle ergometer test to exhaustion (VO2peak), a submaximal cycle ergometer test (VO2submax) at 125 watts, body composition (BC), and thigh cross-sectional area (CSA). A one-way MANOVA revealed a significant within subjects effect of the training program on multiple dependent measures (p = 0.05). Follow-up univariate contrasts were performed to evaluate pre- to post test differences. RESULTS: Group mean data analysis showed a significant 36% increase in 1RM (pre-training = 240.0 ± 62.45 lbs., post training = 324.44± 79.31 lbs., change = 84.44 ± 25.55 lbs.; p =< 0.001), a significant 7.5% increase in CSA (pre-training = 154.66 ± 22.64 cm2, post training = 166.28 ± 23.08 cm2, change = 11.62 ± 7.31 cm2; p = 0.001), and a 6.52% significant decrease in VO2submaxat 125 watts (pre-training = 25.22 ± 2.65 ml/kg/min, post training = 23.57 ± 2.62 ml/kg/min, change = −1.64 ± 1.45 ml/kg/min; p = 0.01). No significant changes were observed in submaximal HR at 125 watts, body weight, or BC. CONCLUSION: Twelve weeks of resistance training, even when designed to comply with ACSM guidelines for increasing cardiorespiratory fitness, increases strength and enhances submaximal exercise performance, but does not result in a significant increase in VO2peak in young adult males.

Prediction methods to account for the effect of gait speed on lower limb angular kinematics

Altering gait speed appears to have an effect on lower limb kinematics during gait. This is a potential source of inaccuracy when data recorded from healthy volunteers are compared with those of slow-walking patients. The aim of this study was to assess the accuracy of several prediction methods which could be used to predict appropriate kinematic data obtained at various walking speeds. Seventeen healthy adults were video-recorded while walking at three different speeds (slow, normal and fast). Five lower limb angles (knee, ankle, thigh, shank and foot) were assessed at 26 points in the gait cycle. Significant correlations were observed between angles and gait speed. The relationship between gait speed and angles was also dependent on the point in the gait cycle that was used for comparison. Results indicate that using prediction methods based on group mean data or regression data from the same speed range on which the prediction methods are being applied is significantly more accurate than prediction methods based on other speed ranges. These results indicate that 'ideal' angle data for slow-walking speeds should be based on data recorded from slow-walking healthy adults or regressed using suitable regression equations.

Posed prosodic emotional expression in unilateral stroke patients: Recovery, lesion location, and emotional perception

Recovery of emotional functioning following stroke has received limited attention in the neuropsychological literature. By emotional functioning, we refer to a range of processing modes, including perception, expression, experience, and behavior. The aim of the current study was to evaluate the course of prosodic emotional expression over time in individuals with stroke. Posed prosodic expression tasks from the New York Emotion Battery were administered to right brain-damaged (RBD), left brain-damaged (LBD), and demographically matched normal control (NC) participants at two separate testing times (median interval of 25 months). Posers (i.e., individuals producing the emotional expressions) were required to produce neutral-content sentences using four different emotional tones (happiness, sadness, anger, and fear). Raters judged poser output for accuracy, intensity, and confidence. For accuracy ratings, RBDs and LBDs were impaired relative to NCs at baseline. In terms of recovery, there was a tendency for LBDs to improve over time, and there was a significant decline for RBDs. Inspection of the group mean data suggested that frontal lesions had a negative impact on prosodic emotional expression in RBDs and that lesion extent did not systematically influence performance at baseline or over time. Participants maintained their relative standing on the NYEB expression tasks over time. Finally, no significant relationships were found between participant performance on prosodic emotional perception and expression tasks at either testing time, suggesting that these two processing modes are relatively independent.

Evaluation of the Immunotech Cyclosporine Direct Radioimmunoassay for the Determination of Whole-Blood Cyclosporine in Renal Transplant Patients

Therapeutic drug monitoring (TDM) of cyclosporine (CsA) has been an accepted as an essential tool in the management of solid organ transplant recipients. The authors evaluated a new CsA method, Immunotech cyclosporine direct radioimmunoassay (Beckman Coulter, Prague, Czech Republic), for the measurement of whole-blood CsA concentrations. The performance was compared with CEDIA Plus method as well as group mean data for HPLC and other immunoassays available from the International CsA Proficiency Testing Program (www.bioanalytics.co.uk). Regression analysis of patient samples gave a relationship of RIA = 1.0822 CEDIA(+) + 69.84 (r(2) = 0.933). External CsA-spiked proficiency-testing (PT) samples gave a regression equation of RIA = 0.9672 CEDIA(+) + 4.99 (r(2) = 0.996). The correlation with the CEDIA Plus method using patient specimens (hence, including CsA metabolites) suggested that the test RIA method possibly had slightly inferior specificity for parent CsA. The results suggest that the Immunotech cyclosporine direct RIA kit is suitable for the measurement of whole-blood CsA concentrations and maintained clinically acceptable analytic precision and accuracy, displaying CVs of less than 15% and biases of less than 10%. The PT program CsA-metabolite-free samples showed that calibration between methods was comparable with the possible exception of mFPIA/TDx.

Associations Between Heart Rate, Oxygen Utilization and Muscle Tissue Oxygen Saturation

0444 Endurance performance is predicated on oxygen delivery and utilization. PURPOSE: The purpose of this study was to investigate the associations between non-invasive measures of heart rate, oxygen consumption (VO2) and muscle tissue oxygen saturation (StO2). METHODS: Subjects were 17 amateur male competitive cyclists. Testing entailed having the subject perform a staged cycling test to exhaustion on a Lode Excalibur Sport ErgometerTM and analyzed the riders for heart rate (bpm) via electronic telemetry (PolarTM), VO2 (L*min.-1) (ParVomedics Metabolic SystemTM) and StO2 (%) utilizing near infra-red spectroscopy(NIRS) (Hutchinson TechnologiesTM). Each cycling test began with a warm-up at 50 W (10 min), progressed to 75 W (2 min), then increased to 100 W. Once tension was set at 100 W, each stage inclusive the 100 W stage lasted 4-min and progressed 25 W every 4-min until the rider reached exhaustion or could no longer maintain a pedal cadence of 50 rpm. Data was collected breath-bybreath, beat-by-beat and in 4 sec. intervals for VO2, HR and StO2, respectively. All data was averaged in 60-second time increments for each subject, and then averaged for each minute between subjects to allow for group mean data for the variables chosen for analysis. Statistical procedures included a Pearson Product R correlation coefficient and regression analysis to determine associations and predictive capabilities between variables, respectively. Statistical significance was set at p < 0.05. RESULTS: Subject characteristics were: age 31.1 (2.5) y; weight 77.2 (2.4) kg; height 178.7 (2.5) cm. Exercise peak averaged across subjects were: VO2peak 4.4 (L*min−1); HR peak); 172 (bpm); StO2peak 87 (%) saturated, 22 (%) de-saturated. Correlation coefficients were significant (p < 0.001) with the following: HR vs. StO2 (R = −0.94); VO2 vs. StO2 (R = −0.91); and HR vs. VO2 (R = 0.97). Regression analyses indicated significant prediction of StO2 from HR (R2 = 0.88) and VO2 (R2 = 0.84). CONCLUSIONS: Muscle tissue oxygen saturation measures are significantly inversely related to increases in heart rate and oxygen consumption. Therefore, specific muscle oxygen levels are associated with oxygen delivery and utilization.

Correlations among evoked potential thresholds, distortion product otoacoustic emissions and hair cell loss following various noise exposures in the chinchilla

Changes in cubic distortion product otoacoustic emissions (ΔDPOAEs), evoked potential threshold shifts (TSs) and outer hair cell (OHC) losses were measured in a population of 95 noise-exposed chinchillas. Each animal was exposed to one of 23 different noises in an asymptotic threshold shift (ATS) producing paradigm or an interrupted noise paradigm which typically produced a toughening effect. Noises were narrow band (400 Hz) impacts with center frequencies of 0.5, 1.0, 2.0, 4.0 or 8.0 kHz presented 1 impact/s at peak SPLs of 109, 115, 121 or 127 dB. The duration of the exposures was 24 h/day for 5 days (ATS paradigm) or 6 h/day for 20 days (toughening paradigm). Based on a linear regression analysis of individual subject and group mean data, correlations among the following dependent variables were made: ΔDPOAEs, ATS, toughening or TS recovery (TS r), permanent threshold shift (PTS) and OHC loss. Correlations among these metrics were generally highest for DPOAE primary frequency levels, L 1= L 2=70 dB. Correlation between ΔDPOAE and TS r was typically low, while a considerably higher correlation was found between ΔDPOAE and ATS. Correlations among the permanent measures of noise-induced effects, i.e. for ΔDPOAE/PTS and ΔDPOAE/OHC loss were typically poor when there was only a small or a moderate noise-induced effect (PTS<25 dB and ΔDPOAE<20 dB). However, for PTS<25 dB the correlation between PTS and OHC loss was considerably better than the correlation between ΔDPOAE and OHC loss. For more severe noise-induced changes there was generally a good correspondence between OHC loss, PTS and ΔDPOAE metrics.

Sniff nasal inspiratory pressure in children.

Maximal static inspiratory pressure (P(IMAX)) generated at the mouth is one of the tests of inspiratory muscle strength in children. In adults, inspiratory muscle strength has also been assessed using sniff nasal inspiratory pressure (SNIP). This test is easier to perform than P(IMAX) and might therefore be applicable to children. To test this hypothesis, we measured P(IMAX) and SNIP in 116 children aged 4 to 11 years (54 girls, 62 boys). P(IMAX) was measured using a tube mouthpiece and SNIP using a tightly fitting plug in one nostril, while a sniff was performed through the other nostril. Both tests were performed from functional residual capacity (FRC). Pressure was measured with a differential pressure transducer and displayed in real time on a computer screen. Weight, standing height, sitting height, gender, and age were recorded. There was a significant difference (P < 0.01) in group mean (SD) data between SNIP (81.3 (27.4) cmH(2)O) and P(IMAX) (67.9 (28.1) cmH(2)O). Bland/Altman analysis demonstrated a mean difference of -13.5 cmH(2)O (SD 21.4) between the techniques. Regression analysis indicated highly significant relations (P < 0.01) between SNIP and P(IMAX), and between weight, standing and sitting height, and age for SNIP, and between weight, standing height, and age for P(IMAX). SNIP and P(IMAX) were greater in boys than girls (83.2 vs. 79.2 cmH(2)O SNIP; 72.9 vs. 62.0 cmH(2)O P(IMAX)), but this difference was only significant for P(IMAX) (P < 0.05). SNIP was significantly greater than P(IMAX) (P < 0.01) in both boys and girls. These data suggest that SNIP provides a simple, noninvasive additional test to P(IMAX) for assessing inspiratory muscle strength in children.

Interval timing performance in temporal lobe epilepsy: differences between patients with left and right hemisphere foci

This experiment examined interval timing performance on a temporal reproduction procedure and a temporal discrimination (interval bisection) procedure in 19 patients with temporal lobe epilepsy (ten with a left-hemisphere focus [LTE group] and nine with a right- hemisphere focus [RTE group]), and 14 normal control subjects. In the temporal reproduction task, subjects were required to reproduce the durations of visual stimuli (0.5, 1, 2, 4, 8 s). In the temporal discrimination task, subjects were required to classify the visual stimuli as either ‘short’ or ‘long’. Following exposure to the two standard durations (1 and 2 s), ‘probe’ trials were introduced in which the stimulus was presented for durations intermediate between the two standard durations. Psychophysical functions were derived from both timing tasks for each individual subject, as well as for the group mean data. The results showed that, compared to the normal subjects, the RTE group’s timing ability was significantly compromized, as reflected by larger Weber fractions in both timing tasks. The LTE group’s Weber fractions did not differ significantly from those of the control group; however they showed a leftward shift (i.e. a shorter bisection point) of the psychophysical function under the temporal discrimination task. The results suggest that the right and left hemispheres may play different roles in regulating interval timing performance.

The Influence of Heal Lift Manipulation on Sagittal Plane Kinematics in Running

In this study sagittal plane joint angles of the lower extremity were used to obtain an indication of the influence of heel lift manipulation on Achilles tendon strain in running. The influence of increased heel lift on lower extremity kinematics was investigated for 8 heel striking subjects. With increased heel lift, all subjects demonstrated reductions in peak ankle dorsi-flexion and consistent values of peak knee flexion, indicating that there were reductions in peak Achilles tendon strain. Group analysis demonstrated that the reductions in peak ankle angle were statistically significant (p &lt; .01). Typically, subjects also demonstrated adjustments in initial ankle angle, whereby the amount of ankle dorsi-flexion at initial ground contact was reduced with increased heel lift. Group mean data indicated that a 15-mm heel lift resulted in a mean decrease in initial ankle dorsi-flexion of 3.9°, while peak ankle dorsi-flexion was also reduced by 3.9°. It is suggested that the initial ankle angle adjustment acted to maintain a similar range of ankle joint movement in the period from initial ground contact to peak ankle dorsi-flexion across heel lift conditions. The distinct behavior of one subject, who demonstrated an increased ankle dorsi-flexion at ground impact, has highlighted the importance of considering single subject results in studies of footwear variation in running.

Genotype and phenotype in hypochondroplasia.

Mutations in the tyrosine kinase domain of fibroblast growth factor receptor gene (FGFR3) have been described in some cases of hypochondroplasia (Hch). We screened 65 children with Hch diagnosed by clinical and radiologic criteria for 2 previously described mutations, C1620A and C1620C in FGFR3; 28 (43%) of 65 patients were heterozygous for the C1620A transversion resulting in lysine to asparagine substitution at codon 540 in the tyrosine kinase domain of FGFR3. The height, sitting height, and subischial leg length of these children and of 18 children with achondroplasia were analyzed at presentation, and SD scores were calculated. For comparison of growth data the patients were divided into three groups: group 1, achondroplasia defined by radiology and the presence of the G1138A mutation in the transmembrane domain of FGFR3; group 2, Hch with C1620A mutation; and group 3, Hch with no mutation identified so far. Height, sitting height, and subischial leg length SD scores were analyzed as group mean data by analysis of variance with the Student Neuman-Keuls test after testing for multiple contrasts were performed. All three groups were significantly compromised in height, although the children with achondroplasia were much shorter with significant reduction in subischial leg length. The same pattern was evident in group 2, with additional shortening of the back, the third group was proportionately short. Children with the common C1620A mutation met all of the criteria for the diagnosis of Hch with a severe phenotype that resembled achondroplasia and disproportionate short stature in early childhood. However, a substantial number of patients with proportionate short stature presented at an older age with the same radiologic characteristics and failure of the puberty growth spurt. The genetic basis of this milder phenotype not yet known.

Interrupted noise exposures: threshold shift dynamics and permanent effects.

A parametric study of the reduction of threshold shift (toughening phenomena) that takes place during the course of an interrupted noise exposure is described. 266 chinchillas randomly assigned to one of 32 experimental groups were exposed to one of the following: a 400-Hz narrow-band impact noise having a center frequency of 0.5, 1.0, 2.0, 4.0, or 8.0 kHz and peak sound-pressure levels of 109, 115, 121, or 127 dB. The impacts were presented for 5 d, 24 h/d or for 20 d, 6 h/d. corresponding pairs of exposures had equal energy. Group mean noise effects were estimated from pure-tone threshold obtained form inferior colliculus evoked potentials and from surface preparation histology. The threshold shift (TS) toughening phenomena is shown to occur in response to all stimuli that produce a TS and at all audiometric test frequencies. The amount of toughening, which is limited to less than 35 dB, varies with noise frequency and intensity. Based on group mean data the auditory system is not protected from the permanent effects of an interrupted noise exposure as a result of the toughening effect but rather differences in permanent effects between the 5- and 20-d exposures are attributed to the spreading of the exposure energy over an extended period of time.

A new method for data presentation in incremental cardiorespiratory exercise testing.

In incremental cardiopulmonary exercise testing, the averaging of data is usually performed to provide group mean data for statistical purposes. They are usually presented as averaged maximum values, or as averaged data at different exercise levels. However, during incremental exercise testing the change in metabolic status may vary between subjects, thus averaging data may not classify the metabolic status accurately. We present an averaging method using a segmented ordinal scale based on individual maximal work performance and the anaerobic threshold (AT). Individual exercise data are grouped into ten classes ranging from unloaded exercise to maximal exercise. The classes are defined in relation to the AT, resulting in an ordinal scale of four classes for exercise data below the AT, one class at the AT and five classes beyond the AT. Resting and unloaded pedalling are treated as separate classes. For evaluation, this method of classification is compared to one based on an absolute scale of oxygen uptake (Cabs) and to another based on a relative scale in 10% steps of maximal oxygen uptake (Crel). Ten healthy male subjects (mean age 23.3 years) performed a ramp cycle ergometer test. When using the Cabs classification method for mean data averaging, mean values for performance at high-intensity exercise were calculated using data from only two of the ten subjects because of variations in individual work capacity. In addition, the AT data were distributed across four classes, thus anaerobic and aerobic exercise data were mixed. Using the Crel classification method enabled data for all ten subjects to be included in the calculation of every data point, but the AT values were still distributed across three classes, resulting in the mixing of anaerobic and aerobic exercise data. However, using the segmented ordinal scale method of classification enabled data from all ten subjects to be included in the calculation of all data points, and it permitted the grouping of the AT values into one class. Thus, this latter method more accurately represents the data of the whole group under study and it allows the metabolic status of the subjects to be taken into consideration.

The cubic distortion product otoacoustic emissions from the normal and noise-damaged chinchilla cochlea.

A normative study of the cubic distortion product emissions from 104 monaural and binaural chinchillas was undertaken to establish criteria upon which noise exposed animals could be evaluated. From this normative group, 47 randomly selected chinchillas were exposed to various high level (150-, 155-, and 160-db peak SPL) impulse noises. Auditory evoked potentials and cubic distortion product otoacoustic emissions were measured on each animal pre- and post-exposure and related to the sensory cell populations 30 days post-exposure. Both group mean and individual animal data indicated that the distortion product emissions were more sensitive, frequency-specific indices of noise-induced cochlear effects than pure-tone threshold measures. This was particularly evident near the threshold for noise-induced damage to the outer hair cell system.

Tubuloglomerular feedback responses to acute contralateral nephrectomy

After unilateral nephrectomy adaptive events must occur in the remaining kidney within the first 12-14 h in anticipation of an increase in glomerular filtration rate (GFR) and eventual renal hypertrophy. Utilizing micropuncture and microperfusion techniques in the rat, we have examined tubuloglomerular feedback (TGF) and single-nephron GFR (SNGFR) responses while the late proximal tubule was microperfused [late proximal tubule flow (VLP)] from 0 to 40 nl/min in 10 nl/min intervals at 2-4 and 12 h after contralateral nephrectomy. Urinary excretion increased, but SNGFR derived from distal collections was reduced, and early distal flow rate remained constant 2-4 h after nephrectomy. The operating point was shifted, suggesting activation of TGF. The turning point half-maximal activity (V1/2) and slope were not statistically different when all nephron data were submitted to a curve-fitting procedure, but group mean data suggested a quantitatively lower V1/2 and steeper slope of the TGF profile. Twelve to fourteen hours after contralateral nephrectomy, values for SNGFR at all microperfusion rates were increased, as were late proximal and early distal flow rates. The values for V1/2 and slope of TGF were not statistically different from control values. We conclude that TGF activity and sensitivity are not suppressed at 2 and 12 h after nephrectomy. Increased urinary excretion does not require TGF alterations. Changes in TGF may be adaptive to increases in SNGFR and may not be causal to the increase in filtration rate after nephrectomy.

Dichotic listening performance to CVs between versus within groups

The present study is concerned with comparing group mean data between groups with individual performance within groups in dichotic listening (DL). It is argued that only comparing mean ear performance in dichotic listening between groups may obscure important individual differences within groups in DL performance. In the present study we compared between group vs. within group performance in four groups of subjects (male and female, right‐ and left‐handers). The stimuli were 66 trials of consonant‐vowel combinations with the six stop‐consonants and the vowels a and u. The results showed a group mean right ear advantage for consonants in the two right‐handed groups, and a left‐ear advantage in the two let‐handed groups. The analysis of the individual distributions within each group, however, showed clear differences between the male and female groups. Generally, though, only the male right‐handed group revealed enough homogeneity within the group to warrant the conclusion that the group mean REA reflects a left hemisphere specialization for speech perception.

Comparative Digestible Energy Requirements of Adult Beagles and Domestic Cats for Body Weight Maintenance

Digestible energy (DE) needs for body weight maintenance (BWM) of six adult Beagles and six domestic cats were comparatively assessed by using data from thirteen 14-day and nine 21-day consecutive apparent digestibility trials, respectively. In each trial the Beagles and cats were given different commercial foods, and feces were quantitatively collected excluding the first 7 days. The relationship between mean daily body weight change (ΔBW) per trial and DE intake was examined by regression analysis of data for individual animals. Pooled mean (n=6) data from 223 Beagle and 143 cat digestibility trials were analyzed by the same method. Significant (P < 0.05) linear regressions between ΔBW and DE intake were obtained (R2 = 0.43-0.93) for all individual Beagles, five of six cats and pooled mean data for both Beagles and cats. Mean (range) daily DE needs for BWM of six individual Beagles were 70 (63–78), 140 (127–146) and 173 (156–187) kcal for data scaled to kilograms, kilograms0.75 and kilograms0.67 BW, respectively. Respective values for six individual cats were 76 (56–89), 104 (86–114) and 114 (95–122) kcal. Analysis of group mean data for Beagles and cats generated daily DE costs for BWM of 76 and 66 kcal/kg, respectively, equivalent to 148 and 95 kcal/kg0.75. Thus adult cats had significantly (P < 0.001) lower energy costs of BWM than Beagles when scaled to metabolic BW (kilograms0.75 or kilograms0.67), but not on an absolute BW basis.

The consistency of cardiac output measurement (CO2 rebreathe) in children during exercise.

Exercise cardiac output (Q) was determined using the CO2 rebreathing equilibrium method. Five repeat tests in 12 boys and two tests over a 4 month interval in 47 boys were performed. Regression equations to predict Q from VO2 were in close agreement with dye dilution studies in boys (Eriksson and Koch 1973). Group mean data were reproducible from trial to trial. The day-to-day variability of Q, with a coefficient of variation of 7-8%, was found to be higher than when the CO2 method has been applied in adults. This greater variability was related, in part, to a larger biological variation in children as depicted in such relatively simple measures as submaximal exercise heart rate. The larger variability was also related to inaccuracies in the methods of PaCO2 estimation in children. Estimation from end-tidal CO2 concentrations requires further research to establish a correction for the alveolar-arterial gradient during exercise in children. Estimation of the child's dead space in exercise, with subsequent derivation of PaCO2 from the Bohr equation, also could be improved. Nevertheless, Q estimates in children exercising above VO2 1.01 X min-1 showed a day-to-day and long term stability acceptable for use in research and clinical studies.

Amoxapine (Asendin, Lederle Laboratories).

Amoxapine is a tricyclic antidepressant agent, which is chemically related to the antipsychotic agent loxapine, but which appears to block selectively the neuronal reuptake of norepinephrine; it is qualitatively similar to desipramine. In studies of patients with mixed depressive illnesses, amoxapine is at least as effective as amitriptyline and imipramine and probably more effective than placebo in ameliorating depressive symptoms. Claims of more rapid onset of therapeutic effects are based on group mean data obtained from small samples of depressed patients with heterogeneous and imprecisely defined diagnostic types. Amoxapine has yet to be compared with desipramine or maprotiline, the most pharmacologically similar antidepressants. Biopharmaceutical and pharmacokinetic data are limited, and a relationship between serum concentrations and efficacy has not yet been shown. Acute toxicity and drug interaction documentation are also lacking. At this time, amoxapine represents a chemical alternative to traditional tricyclic antidepressants. There are no consistent data indicating superiority of amoxapine over any other antidepressant agent for any specific symptom constellation, in rate or extent of improvement, or in any particular diagnostic or demographic population. Studies in which amoxapine is compared with pharmacologically similar agents at therapeutically equivalent doses in diagnostically homogeneous groups are needed to establish the drug's true place in the treatment of depressions.

Photoplethysmography in the Prediction of Experimental Flap Survival

A standard photoplethysmograph, modified to differentiate between arterial and venous vasculature in skin tissue, has been used to measure arterial supply in 100 unipedicle skin flaps in 25 pigs. A datum transform from a light intensity scale to a relative arterial blood density scale has been introduced and empirically labelled the vascular coefficient (VC). Statistical analysis of the VC data shows a significant difference between necrotic and surviving flap group mean data as early as 24 hours. Additional analysis in which a normal ogive was fitted to the sample VC data distributions suggests that statistically significant predictions of the probability of eventual flap necrosis can be made using VC measurements obtained immediately postoperatively. It is concluded that the modified photoplethysmograph in conjunction with the VC data transform, constitutes a usable measuring technique for skin flap viability prediction in the experimental animal.

The role of photoplethysmography in the prediction of the experimental flap survival.

A standard photoplethysmography, modified to differentiate between arterial and venous vasculature in skin tissue, has been used to measure arterial supply in 100 unipedicle skin flap in 25 pigs. A datum transform from a light intensity scale to a relative arterial blood density scale has been introduced and empirically labeled the vascular coefficient (VC). Statistical analysis of the VC data shows a significant difference between necrotic and surviving flap group mean data as early as 24 hours. Additional analysis in which a normal ogive was fitted to the sample VC data distributions suggests that statistically significant predictions of the probability of eventral flap necrosis can be made using VC measurements obtained immediately postoperatively. It is concluded that the modified photoplethysmograph, in conjunction with the VC data transform constitutes a usable measuring technique for skin flap viability prediction in the experimental animal.