Exercise plus n-3 fatty acids: additive effect on postprandial lipemia

The purpose of this study was to examine changes in postprandial lipemia (PPL) in recreationally active males following aerobic exercise, omega-3 fatty acids (n-3FA) supplementation, and the combination of the two. PPL following a high-fat meal was measured in 10 recreationally active males (25 +/-1.5 years) under each of the following conditions: no exercise and no n-3 FA supplementation (control); exercise and no n-3FA supplementation (exercise); n-3FA supplementation and no exercise (n-3FA); and exercise and n-3 FA supplementation (combined). Blood was collected before the high-fat meal and at 2, 4, 6, and 8 hours after the meal to assess the PPL response. Supplementation consisted of 4.0 g of n-3FA per day for 5 weeks. Triglyceride (TG) peak response, the total area under the TG curve (TG-AUCT), and the incremental area under the TG curve (TG-AUCI) were used to define the PPL response. TG peak response was significantly reduced 38% by n-3FA supplementation and 50% by the combination of exercise and n-3FA supplementation. N-3FAs significantly reduced the TG-AUCT by 27% and by 42% when combined with exercise. When compared with the exercise trial, the TG-AUCT during the combined trial was significantly lower. Exercise, n-3FAs, and the combination significantly reduced the TG-AUCI by 40%, 42%, and 58%, respectively. These results suggest that the combination of exercise and n-3FA supplementation reduce PPL to a greater degree in recreationally active males when compared with the individual treatments.

Effects of omega-3 fatty acid supplementation and exercise on low-density lipoprotein and high-density lipoprotein subfractions

The purpose of this study was to examine the effect of combining exercise with omega-3 fatty acids (n-3fa) supplementation on lipoprotein subfractions and associated enzymes. Subjects were 10 recreationally active males, aged 25 +/- 1.5 years (mean +/- SE), who supplemented n-3fa (60% eicosapentaenoic acid [EPA] and 40% docosahexaenoic [DHA]) at 4 g/d for 4 weeks. Before and after supplementation, subjects completed a 60-minute session of treadmill exercise at 60% Vo(2)max. Following a 24-hour diet and activity control period, blood was collected immediately before and after the exercise session to assess lipid variables: high-density lipoprotein cholesterol (HDL-C) and subfractions, low-density lipoprotein cholesterol (LDL-C) and subfractions and particle size, lecithin:cholesterol acyltransferase (LCAT) activity, and cholesterol ester transfer protein (CETP) activity. Supplementation with n-3fa alone increased total HDL-C and HDL(2)-C, while exercise alone increased total HDL-C, HDL(3)-C, and total LDL-C. LDL subfractions, particle size, and LCAT and CETP activities were not affected by supplementation. Combination treatment resulted in an additive effect for HDL(3)-C only and also increased LDL(1)-C versus baseline. LCAT and CETP activities were not affected by treatments. These results suggest that n-3fa supplementation or an exercise session each affect total HDL-C and subfractions but not LDL-C or subfractions. In addition, the combination of n-3fa and exercise may have additional effects on total HDL-C and LDL-C subfractions as compared to either treatment alone in active young men.

Neural correlates of timbre change in harmonic sounds

Timbre is a major structuring force in music and one of the most important and ecologically relevant features of auditory events. We used sound stimuli selected on the basis of previous psychophysiological studies to investigate the neural correlates of timbre perception. Our results indicate that both the left and right hemispheres are involved in timbre processing, challenging the conventional notion that the elementary attributes of musical perception are predominantly lateralized to the right hemisphere. Significant timbre-related brain activation was found in well-defined regions of posterior Heschl's gyrus and superior temporal sulcus, extending into the circular insular sulcus. Although the extent of activation was not significantly different between left and right hemispheres, temporal lobe activations were significantly posterior in the left, compared to the right, hemisphere, suggesting a functional asymmetry in their respective contributions to timbre processing. The implications of our findings for music processing in particular and auditory processing in general are discussed.

Simultaneous bilateral breast reconstruction using latissimus dorsi myocutaneous flaps: a retrospective review of an institutional experience

A single institution's experience in the simultaneous reconstruction of both breasts using bilateral latissimus dorsi myocutaneous flaps is presented. The procedure was performed on 24 patients by the attending staff of the department of plastic surgery at St. Joseph Hospital in Houston, Texas, between 1979 and 1999. Of the 24 patients reviewed, six had immediate reconstructions, 13 had delayed primary reconstructions, and five had secondary reconstructions of failed or unsatisfactory primary procedures. In the group with delayed reconstructions, the average time between mastectomy and reconstruction was 46.4 months, with a range from 7 days to 21 years. The operative method, results, and outcomes of our experience in these patients is presented.

Signal decomposition method of evaluating head movement to measure induced forelimb lameness in horses trotting on a treadmill

In horses at a trot, the head moves up and down twice in one stride. In horses with unilateral forelimb lameness this movement is asymmetric. Computer-assisted kinematic analysis of vertical head movement can be used to quantify objectively lameness in horses in clinical trials. However, in mild lameness, absolute measurements of vertical head height may not be sensitive enough to detect small differences in lameness, and extraneous head movement by the horse due to curiosity, excitement or nervousness interferes with the accurate measurement of vertical head movement asymmetry. We describe a simple, signal-decompensation method of evaluating vertical head movement using a model of induced mild foot lameness in 9 horses. The technique assumes that the vertical head movement pattern can be broken down into 3 components; the vertical head movement caused by forelimb lameness (A1), the amplitude of the natural biphasic vertical head movement (A2) and extraneous head movement. Extraneous head movement is mathematically removed from the vertical head movement pattern. A1 and A2 are then calculated. After induction of lameness, mean A1 increased by 1.63 cm (range 0.10-3.33 cm, P = 0:005). Mean A2 did not significantly change after lameness induction. Error in reproduction of the original head movement pattern was 0.3-0.5%. We calculated that a hypothetical clinical trial would require 12 subjects for testing to be 80% certain that this difference would be successfully detected using this method of lameness evaluation.

Increased flavor preference and lick activity for sucrose and corn oil in SWR/J vs. AKR/J mice

Nutrient preferences and orosensory responses were characterized in two mouse inbred strains. In two-bottle solution tests (tastant vs. vehicle; ascending concentrations), the effects of strain and chow type (12 or 26% fat) on preference thresholds for sucrose and corn oil were compared in AKR/J and SWR/J mice. SWR/J mice displayed lower preference thresholds and ingested more sucrose than AKR/J mice did. SWR/J mice also showed lower preference thresholds and consumed more corn oil than AKR/J mice did; corn oil preference was suppressed 3.5-fold in AKR/J mice compared with SWR/J mice when fed 26% fat chow. Next, licking was recorded during 30-s access to sucrose or corn oil across a range of concentrations. SWR/J mice licked the tastants more than AKR/J mice did. Analysis of modal interlick intervals during lick training revealed that SWR/J mice licked water faster than AKR/J mice when water deprived, suggesting that motor as well as sensory factors may determine lick responses to tastants in brief-access tests. Finally, in two-bottle tests pitting maximally preferred concentrations of sucrose (8 or 16%) against corn oil (20%), SWR/J mice highly preferred sucrose over corn oil at either sucrose concentration. AKR/J mice preferred corn oil over 8% sucrose but reversed their preference when 16% sucrose was offered. These results support a primary role of flavor in the nutrient preferences of SWR/J mice. In AKR/J mice, the low lick activity for sucrose and corn oil and greater suppression of corn oil preference by the high-fat chow suggest that their preferences depend more on postingestive factors than on flavor.

Capsaicin-treated rats permanently overingest low- but not high-concentration sucrose solutions

The effect of capsaicin-induced chemical ablation of visceral afferents on 1-h liquid sucrose consumption was investigated in food-deprived rats. We first show that although 10% sucrose is permanently overconsumed by capsaicin-treated (CAPs) compared with vehicle-treated (VEHs) control rats, 40% sucrose is only overconsumed during the first but not subsequent 1-h exposures. Furthermore, one group of CAPs lost the overconsumption response at 20% when exposed to progressively increasing sucrose concentrations of 10-40%, and another group recovered the overconsumption response at 10% when exposed to a series of decreasing concentrations. Control rats ingested relatively constant volumes of sucrose over the range of 10, 15, and 20%, resulting in significantly different energy intakes. In contrast, CAPs generally showed a concentration-dependent decrease in volume intake, resulting in relatively constant energy intake. These results suggest that capsaicin-sensitive visceral afferents, likely from gastric distension and other preabsorptive sensors, provide major control over volume ingested. In the absence of these signals, rats initially overconsume, but rapidly learn to use other signals from capsaicin-resistant preabsorptive or postabsorptive sites, to control future intake. This redundant satiety system appears to be sensitive to the osmotic value or caloric content of the unfamiliar food, but only if this is above a threshold of about 15% sucrose.

Kinematics of the hind limb in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and intra-articular administration of anesthetic

OBJECTIVE

To identify hind limb and pelvic kinematic variables that change in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and after subsequent intra-articular administration of anesthetic.

ANIMALS

8 clinically normal adult horses.

PROCEDURE

Kinematic measurements were made before and after transient endotoxin-induced lameness of the distal intertarsal and tarsometatarsal joints and after intra-articular administration of anesthetic. Fourteen displacement and joint angle (metatarsophalangeal [fetlock] and tarsal joints) measurements were made on the right hind limb, sacrum, and the right and left tubera coxae. Kinematic measurements were compared by general linear models, using a repeated measures ANOVA. Post hoc multiple comparisons between treatments were evaluated with a Fisher least squared difference test at alpha = 0.05.

RESULTS

After lameness induction, fetlock and tarsal joint extension during stance decreased, fetlock joint flexion and hoof height during swing increased, limb protraction decreased, and vertical excursion of the tubera coxae became more asymmetric. After intra-articular administration of anesthetic, limb protraction returned to the degree seen before lameness, and vertical excursion of the tubera coxae became more symmetric.

CONCLUSIONS AND CLINICAL RELEVANCE

Increased length of hind limb protraction and symmetry of tubera coxae vertical excursion are sensitive indicators of improvement in tarsal joint lameness. When evaluating changes in tarsal joint lameness, evaluating the horse from the side (to assess limb protraction) is as important as evaluating from the rear (to assess pelvic symmetry).

Changes in kinematic variables observed during pressure-induced forelimb lameness in adult horses trotting on a treadmill

OBJECTIVE

To determine whether kinematic changes induced by heel pressure in horses differ from those induced by toe pressure.

ANIMALS

10 adult Quarter Horses.

PROCEDURE

A shoe that applied pressure on the cuneus ungulae (frog) or on the toe was used. Kinematic analyses were performed before and after 2 levels of frog pressure and after 1 level of toe pressure. Values for stride displacement and time and joint angles were determined from horses trotting on a treadmill.

RESULTS

The first level of frog pressure caused decreases in metacarpophalangeal (fetlock) joint extension during stance and increases in head vertical movement and asymmetry. The second level of frog pressure caused these changes but also caused decreases in stride duration and carpal joint extension during stance as well as increases in relative stance duration. Toe pressure caused changes in these same variables but also caused maximum extension of the fetlock joint to occur before midstance, maximum hoof height to be closer to midswing, and forelimb protraction to increase.

CONCLUSION AND CLINICAL RELEVANCE

Decreased fetlock joint extension during stance and increased head vertical movement and asymmetry are sensitive indicators of forelimb lameness. Decreased stride duration, increased relative stance duration, and decreased carpal joint extension during stance are general but insensitive indicators of forelimb lameness. Increased forelimb protraction, hoof flight pattern with maximum hoof height near midswing, and maximum fetlock joint extension in cranial stance may be specific indicators of lameness in the toe region. Observation of forelimb movement may enable clinicians to differentiate lameness of the heel from lameness of the toe.

Macronutrient diet selection in thirteen mouse strains

The strain distribution for macronutrient diet selection was described in 13 mouse strains (AKR/J, NZB/B1NJ, C57BL/6J, C57BL/6ByJ, DBA/2J, SPRET/Ei, CD-1, SJL/J, SWR/J, 129/J, BALB/cByJ, CAST/Ei, and A/J) with the use of a self-selection protocol in which separate carbohydrate, fat, and protein diets were simultaneously available for 26-30 days. Relative to carbohydrate, nine strains consumed significantly more calories from the fat diet; two strains consumed more calories from carbohydrate than from fat (BALB/cByJ, CAST/Ei). Diet selection by SWR/J mice was variable over time, resulting in a lack of preference. One strain (A/J) failed to adapt to the diet paradigm due to inadequate protein intake. Comparisons of proportional fat intake across strains revealed that fat selection/consumption ranged from 26 to 83% of total energy. AKR/J, NZB/B1NJ, and C67BL/6J mice self-selected the highest proportion of dietary fat, whereas the CAST/Ei and BALB/cByJ strains chose the lowest. Finally, epididymal fat depot weight was correlated with fat consumption. There were significant positive correlations in AKR/J and C57BL/6J mice, which are highly sensitive to dietary obesity. However, absolute fat intake was inversely correlated with epididymal fat in two of the lean strains: SWR/J and CAST/Ei. We hypothesize that the SWR/J and CAST/Ei strains are highly sensitive to a negative feedback signal generated by increasing body fat, but the AKR/J and C67BL/6J mice are not. The variation in dietary fat selection across inbred strains provides a tool for dissecting the complex genetics of this trait.

Divergence in proportional fat intake in AKR/J and SWR/J mice endures across diet paradigms

These experiments were designed to test the hypothesis that the contrasting patterns of macronutrient selection described previously in AKR/J (fat preference) and SWR/J (carbohydrate preference) mice are not dependent on a single diet paradigm. The effect of mouse strain on proportional fat intake was tested in naive mice by presenting two-choice diets possessing a variety of physical, sensory, and nutritive properties. In three separate experiments, AKR/J mice preferentially selected and consumed a higher proportion of energy from the high-fat diet than SWR/J mice. Specifically, this phenotypic difference was observed with 1) fat-protein vs. carbohydrate-protein diets, independent of fat type (vegetable shortening or lard), 2) isocaloric, high- vs. low-fat liquid diet preparations, and 3) high- vs. low-fat powdered-granular diets. These results confirm our previous observation of a higher proportional fat intake by AKR/J compared with SWR/J mice using the three-choice macronutrient selection diet and show that this strain difference generalizes across several diet paradigms. This strain difference is due largely to the robust and reliable fat preference of the AKR/J mice. In contrast, macronutrient preference in SWR/J mice varied across paradigms, suggesting a differential response by this strain to some orosensory or postingestive factor(s).

Activation of hypothalamic serotonin receptors reduced intake of dietary fat and protein but not carbohydrate

Systemic treatment with dexfenfluramine (dF), fluoxetine, or serotonin (5-hydroxytryptamine, 5-HT) recently was shown to suppress fat and occasionally protein but not carbohydrate intake in rats when a macronutrient selection paradigm was employed. These reports contrast with the prevailing literature, which for the past decade has described a role for serotonin neurotransmission in the modification of dietary carbohydrate consumption. To test the hypothesis that the suppression of fat selection and/or consumption by systemic serotonin agonists involves stimulation of central 5-HT receptors, a series of experiments was performed in nondeprived rats. In experiment 1, third cerebroventricular (3V) infusion of the nonselective 5-HT antagonist metergoline prevented the reduction in fat but not carbohydrate feeding caused by systemic dF. Furthermore, 3V metergoline alone increased fat intake. In experiments 2 and 3, 3V infusion of 5-HT(1B/2C) receptor agonists D-norfenfluramine (DNF) or quipazine inhibited fat intake exclusively. Next, the infusion of DNF or 5-HT into the region of the paraventricular nucleus (PVN) reduced both fat and protein intake (experiments 4 and 5). Finally, in experiment 6, when rats were grouped by baseline diet preference, 5-HT infused into the PVN led to a dose-related decrease in fat intake in both carbohydrate- and fat-preferring rats. In contrast, there were no dose effects of 5-HT on carbohydrate or protein intake in either preference group. However, in fat-preferring rats, the highest dose of 5-HT reduced intake of all three macronutrient diets. These results demonstrate a selective effect of exogenous serotonergic drugs in the hypothalamus to reduce fat rather than carbohydrate intake and suggest that higher baseline fat intake enhances responsivity to serotonergic drugs.

Accuracy of digitization using automated and manual methods

BACKGROUND AND PURPOSE

Computerized 3-dimensional (3-D) motion measurement systems are used by those interested in human motion. The purposes of this study were (1) to determine the limits of accuracy in determining intersegmental angles during pendular motion at varying speeds and (2) to determine changes in accuracy introduced by autodigitization and digitization by experienced manual raters.

METHODS

Angular speed of a T-shaped pendulum was systematically increased by releasing the pendulum from 4 angles (0 degrees [no movement], 45 degrees, 90 degrees, and 120 degrees). Twelve reference angles calculated from markers placed on the pendulum were estimated over 20 frames for 10 trials at each release position.

RESULTS

Mean errors across trials and frames for intersegmental angles reconstructed by a 3-D motion measurement system were within +/- 1 degree across all release positions. An analysis of variance and a post hoc Tukey test revealed that the mean error for the autodigitized trials was larger than that for the manually digitized trials. For the autodigitized trials, the static trials (release position=0 degrees) produced less mean error than the trials with movement produced. The ICCs showed a high degree of consistency among all raters, ranging from .707 to .999.

CONCLUSION AND DISCUSSION

Our findings support the conclusion that under carefully controlled conditions, a 3-D motion measurement system can produce clinically acceptable measurements of accuracy across a range of angular speeds. Furthermore, acceptable accuracy is possible regardless of the digitization method.

Morphological evaluation of a regurgitant orifice by 3-D echocardiography: applications in the quantification of valvular regurgitation

The clinical evaluation of blood flow regurgitation through a heart valve or stenotic lesion is an unresolved problem. The proximal flowfield region has been the study focus in the last few years; however, investigators have failed to identify an accurate and reliable calculation scheme due to lack of geometric information about the shape and size of the regurgitating or stenotic orifice. Presented here is a superior method of calculation, by using three-dimensional (3-D) echocardiography combined with Doppler velocimetry. The geometric structure of the orifice in a regurgitating porcine prosthetic valve in vitro was formulated by 3-D image construction of sequentially obtained 2-D images. The velocity flowfield was accessed by color Doppler flow mapping (CD) and continuous-wave Doppler (CW). Two accurate methods of calculation of regurgitant variables were developed. The first method calculated peak regurgitant flow rate from CD and the second method calculated regurgitant flow volume from CW. Both methods showed excellent correlation with the corresponding true values from an electromagnetic flowmeter. The promising preliminary results in such a realistic porcine model indicate the possibility of establishing a routine procedure to be tested in the clinical setting.

Preferential fat intake increases adiposity but not body weight in Sprague-Dawley rats

It is not known whether an inherent preference for dietary fat promotes obesity in animals allowed to self-select the proportions of fat and carbohydrate consumed. To address this question, Sprague-Dawley rats were given a choice between two diets containing either 78% fat (by energy) or 78% carbohydrate; both diets were equicaloric for protein (22%). The entire study lasted 12 weeks. After an adaptation period, macronutrient preferences were determined by measuring 24 h intake of the two diets for 5 days; fat-preferring animals were classified as those that consumed greater than 60% of total energy from the fat/protein source, and carbohydrate-preferring rats as those that consumed less than 40%. Rats with intermediate macronutrient intakes were excluded. Initial body weight was not different between preference groups. Caloric intakes and body weights were then recorded at approximate weekly intervals, and fat depots were weighed at the time of sacrifice. Measures of energy intake and body weight did not differ between the two preference groups over time. In addition, baseline macronutrient preferences remained stable across the study period. Despite similar body weights, mean epididymal fat depot weight was significantly higher in fat-preferring rats than in carbohydrate-preferring rats (12.6 vs. 10.0 g); also, mean inguinal fat depot weight in fat-preferrers was greater although not reliably different compared to carbohydrate-preferring rats (12.9 vs. 10.9 g). Thus, the preferential intake of fat led to a greater deposition of both subcutaneous and visceral fat without an increase in body weight. These data lead us to conclude that the increased fat deposition was due primarily to the ingestion of fat rather than to excess caloric intake.

Chronic d-fenfluramine treatment reduces fat intake independent of macronutrient preference

We investigated the effect of chronic dexfenfluramine (DFEN) treatment on macronutrient selection in a three-choice diet paradigm using Sprague-Dawley rats. Baseline macronutrient intakes were measured for several days before the initiation of treatment. In Experiment 1, daily intraperitoneal injections of DFEN (1.5 mg/kg) or saline were administered 60 min before dark onset for 12 consecutive days and 24 h macronutrient intakes were measured. DFEN significantly reduced absolute fat intake (kcal) by 30% and relative fat intake (% of total energy) by 14% in animals that received dexfenfluramine treatment compared to controls over the 12-day period. Absolute carbohydrate intake was increased 24% compared to controls, but this difference was not significant. These changes in food intake resulted in a 10% lower total energy intake. Upon discontinuation of the drug, fat intake of the DFEN-treated rats rebounded to control levels within 24 h. In Experiment 2, rats were assigned to carbohydrate- or fat-preferring groups based on the ratio of their average daily carbohydrate to fat intake (kcal). All animals then received DFEN. During DFEN treatment, fat-preferring rats reduced their daily fat intake from 62 to 53% of total energy. The low baseline fat intake of carbohydrate-preferring rats was reduced even further by DFEN (from 24 to 15% of total energy). These corresponding effects of DFEN on macronutrient selection in both fat- and carbohydrate-preferring rats indicate that chronic DFEN treatment selectively suppressed fat intake independent of the preferred macronutrient diet.

Accuracy of reconstructed angular estimates obtained with the Ariel Performance Analysis System

BACKGROUND AND PURPOSE

Three-dimensional computerized gait analysis continues to grow in use among physical therapists and other clinical specialists interested in quantitative data regarding human ambulation. This study documented the accuracy of reconstructed angular estimates under static and dynamic conditions using the Ariel Performance Analysis System.

METHODS

Angular velocity was systematically increased by raising the release position of a T-shaped pendulum. Angular velocities were examined by releasing the pendulum from four angles (0 degree-static, 45 degrees, 90 degrees, and 120 degrees). Twelve reference angles were estimated over 20 autodigitized frames for 10 trials at each release position. Intraclass correlation coefficients (ICCs) and analysis-of-variance (ANOVA) procedures were used to test the hypothesis that the error of angular estimates grows with increasing angular velocity.

RESULTS

Mean errors of the reconstructed angles were consistently within +/- 1.0 degree, regardless of angular velocity. An ANOVA revealed a statistically significant angular velocity effect, characterized by release position. The 90-degree release position produced the greatest error, followed by the 120-, 45-, and 0-degree release positions. The error was not significantly different between the 120- and 45-degree release positions. Intraclass correlation coefficients greater than .90 were found for all frame-to-frame angular velocities, except for the 90-degree release position. The angle estimates consistently underestimated the reference angles, regardless of release position.

CONCLUSION AND DISCUSSION

The results suggest that clinically accurate angular estimates can be obtained across the range of angular velocities used in this study.

Kinematic changes following botulinum toxin injection after traumatic brain injury

The objectives of this study were to: (1) demonstrate the use of computerized, three-dimensional gait analysis as a functional assessment instrument following clinical intervention; and (2) objectively quantify the effects of focal muscle denervation via botulinum toxin type A (BTXA) injection in a hemiparetic patient with lower extremity spasticity following traumatic brain injury (TBI). A desired outcome of this intervention was to realize kinematics more closely resembling those reported for normal patients. The design was a single-subject case study. Ten trials of walking gait were analysed pre-injection (PI), 1 week post-injection (1PO) and 4 weeks post-injection (4PO). The PI and 1PO sessions were found to be appreciably different from the 4PO on the joint angles of the ankle and knee at each phase of the gait cycle. These differences resulted in a reduced asymmetry of ambulation. Stride time, stance time, percentage stance time, percentage swing time and walking speed improved, showing progress towards a more efficient gait pattern. Decreased stride time and increased walking speed supported improved functional ability. The inter-trial variability of the gait parameters showed the analysis to be a consistently reproducible protocol. Conclusions based on the results included encouraging findings for the efficacy of botulinum toxin A as a therapy for the reduction of spasticity.

Carbohydrate versus fat intake: differing patterns of macronutrient selection in two inbred mouse strains

As a first step toward developing a mouse model to characterize genetic factors linked to the preferential intake of dietary carbohydrate or fat, we have identified two mouse strains that exhibit distinctly different patterns of macronutrient selection. Macronutrient selection was evaluated in AKR/J and SWR/J mice, two strains that have been characterized previously for their sensitivity to high-fat dietary obesity. Mice were adapted to a self-selection protocol in which separate carbohydrate, fat, and protein sources were simultaneously available. AKR/J mice ate 30% more calories than the SWR/J mice. Furthermore, strain comparisons revealed a significantly higher proportion of fat intake by the AKR/J mice (69 vs. 28%), and in the SWR/J mice a significantly higher intake of carbohydrate (62 vs. 24%). The mice were then returned to a standard chow diet for 10 wk. These mice subsequently were allowed to self-select from two composite energy diets (carbohydrate and protein, or fat and protein). Once again, AKR/J mice selected a greater proportion of energy from the fat/protein diet (85%) than did the SWR/J strain (32%). These findings suggest a possible relationship between sensitivity to dietary obesity and fat selection.

Differential effects of baseline macronutrient preferences on macronutrient selection after galanin, NPY, and an overnight fast

Rats display individual patterns of fat and carbohydrate intakes when allowed to self-select among individual macronutrient diets. We investigated whether these individual preferences in macronutrient selection could be modified by an overnight fast or by two orexigenic peptides, galanin and neuropeptide Y (NPY), which may selectively stimulate fat and carbohydrate intake. Rats were grouped by preference based on the ratio of average baseline fat:carbohydrate intake. In counterbalanced tests conducted on separate days, saline, galanin, or NPY was infused into the paraventricular nucleus of the hypothalamus and 60-min food intake was measured. When the macronutrient intakes were expressed as percent of total caloric intake, galanin administered into the PVN did not increase fat consumption compared to saline injection in either preference group. NPY slightly enhanced the proportion of carbohydrate intake, but only in carbohydrate-preferring rats. When all three feeding stimuli were compared to baseline preferences, the only condition that significantly altered macronutrient selection was an overnight fast, which augmented fat intake. These data demonstrate that baseline preferences for fat or carbohydrate are not significantly modified by galanin or NPY but that an overnight fast increases fat preference.

Effects of dietary preference and galanin administration in the paraventricular or amygdaloid nucleus on diet self-selection

Microinjection of galanin into the paraventricular nucleus (PVN) of the hypothalamus has been reported to predominantly increase dietary fat consumption during the light or late dark periods. However, there have been no studies of the macronutrient-specific effects of galanin administered into the amygdala (AMY). We used male Sprague-Dawley rats to test the effect of galanin administered into the PVN or central nucleus of the AMY on diet selection using two different protocols: the two-choice composite diet (10% or 55% energy as fat) (Study 1) or the three-choice macronutrient diet (Study 2). In the first study, total food intake was significantly increased 60 min after galanin injection (0.3 nmol) into either the PVN or AMY, but there was no difference in intake between the low- and high-fat diets. In Study 2, using the three-choice macronutrient diet, the feeding stimulation produced by galanin in the PVN also was not diet-dependent. In the AMY, there was a significant effect of diet on the feeding response to galanin, due primarily to the lack of stimulation of protein intake, whereas the intakes of fat and carbohydrate were not significantly different. In summary, there was no difference in the effect of galanin on fat versus carbohydrate intake for either nuclei, whether animals were injected during the light or the late-dark phase. Because rats often display preferences when allowed to choose among individual macronutrient sources, we also examined the relationship between baseline macronutrient preference and the feeding response to galanin in groups of highly fat-preferring and carbohydrate-preferring rats (Study 3). After PVN galanin injection, fat-preferring rats demonstrated significant increases in their consumption of both carbohydrate and fat, whereas carbohydrate-preferring rats responded by eating carbohydrate almost exclusively. There were significant positive associations between baseline macronutrient intake and galanin-induced intake. The results of these studies combined suggest that the effect of galanin on macronutrient selection is not specific for fat and that underlying macronutrient preferences are important in determining the feeding response to galanin.

Development of altered taste preferences in tumor-bearing rats

Experimental tumors induce a decline in food intake that may derive from changes in taste or the development of taste aversions. The preferences of tumor-bearing (TB) and non-tumor-bearing (NTB) rats for five chemicals (three palatable and two aversive taste stimuli) were studied in an animal model of experimental cancer employing the methylcholanthrene (MCA) sarcoma. In protocol 1, five groups of Fischer 344 rats were given 23-h, two-bottle preference tests (taste solution vs. water) daily from day 3 after tumor implantation until spontaneous death occurred. Both NTB and TB rats avoided quinine hydrochloride and hydrochloric acid solutions throughout the experiment indicating that tumor growth produced no disruption in the animals' perception of these normally aversive tastes. In both groups, preference for sucrose (88% to 97%) and saccharin (75% to 93%) remained high until days 22 and 17 respectively, but tended to decline with advanced tumor growth. In both cases, a reduction in total calorie intake preceded the changes in sucrose or saccharin preference by several days. With or without a tumor, rats exhibited approximately 50% preference for NaCl at all times. In protocol 2, a four-bottle preference test (sucrose vs. saccharin vs. NaCl vs. water) was administered before tumor implantation and again 3 weeks later when a decline in food intake was evident. Both TB and NTB rats displayed a dominant preference for sucrose over saccharin, NaCl, and water at the pre- and posttests. However, a comparison of the difference scores (pre- minus postimplantation) of NTB and TB rats showed a small but significant suppression of TB animals' preference for sucrose. The altered preferences for sweet but not salt taste stimuli suggest that food-related taste cues may be more susceptible to the development of taste aversions during cancer. However the contribution of taste changes to the anorexia of cancer remains unclear and it is possible that the changes in taste preference may be secondary to the reduction in food intake.

Effects of cholinesterase inhibitors on the neuromuscular blocking action of suxamethonium

Prolonged neuromuscular block occurs when suxamethonium is given after neostigmine or pyridostigmine; however, studies of edrophonium and suxamethonium have yielded conflicting results. We have studied, therefore, interactions between suxamethonium and all three anticholinesterases in rats anaesthetized with pentobarbitone. After recovery from an initial bolus of suxamethonium, saline, edrophonium, pyridostigmine or neostigmine was administered and a second dose of suxamethonium was then given. All three anticholinesterases prolonged the duration of neuromuscular block (90% suppression to 50% twitch recovery) to 127 (SEM 9)%, 127(10)% and 138 (11)% of baseline for edrophonium, pyridostigmine and neostigmine, respectively. Recovery index (25% to 75% twitch recovery) was increased also to 125 (9)%; 149 (10%) and 185 (15)% of baseline, respectively for the three drugs.

Chronic cerebroventricular galanin does not induce sustained hyperphagia or obesity

Acute central administration of galanin has been reported to increase fat consumption. These experiments were designed to test the hypothesis that repeated injections of galanin would elicit hyperphagia and weight gain and that this response would depend on the available diet. Male Sprague-Dawley rats were fed high (56% energy) or low (10% energy) fat diets. Galanin (300 pmol) or saline vehicle was injected into the third ventricle twice daily for 7 days and three times daily for another 6 days. On both the high-carbohydrate and high-fat diets, twice daily galanin increased daytime food intake, but there was a compensatory decrease in nighttime intake. The addition of a third, nighttime injection of galanin was ineffective in producing an increase in total 24-h intake. There was no significant increase in body weight during galanin treatment in rats eating either diet although animals eating the high-fat diet gained more weight as reflected by a significant increase in epididymal fat pad weight. Galanin treatment had no effects on serum insulin, glucose or corticosterone concentrations, measured at the end of the experiment. However, animals fed the high-fat diet had significantly higher insulin concentrations at the time of sacrifice. Although repeated central infusions of galanin reliably stimulated daytime intake of both diets, they failed to increase total daily energy intake or body weight.

Anti-TNF-alpha antibodies normalized body temperature and enhanced food intake in tumor-bearing rats

Anorectic weight-losing Fischer 344 rats bearing a methylcholanthrene-induced sarcoma received intraperitoneal injections of rabbit antiserum raised against murine tumor necrosis factor (TNF)-alpha at 14, 18, and 24 days after tumor induction. Treatment of tumor-bearing rats with TNF antiserum partially reversed the tumor-induced reduction in food intake compared with tumor-bearing rats that received control serum. In the same tumor-bearing animals, treatment with TNF antiserum delayed the onset and significantly reduced the decline in mean 12-h daytime and nighttime intra-abdominal temperatures on days 18-25. However, anti-TNF antibody treatment did not alter the declines in carcass weight or motor activity measured from day of tumor induction until death or reduce the tumor burden at death. We conclude that an endogenous TNF response may be one of the factors involved in the development of cancer anorexia and that this cytokine has temperature-lowering properties.

Experimental cachexia: effects of MCA sarcoma in the Fischer rat

Temporal patterns of the cachectic effects of tumor growth and their relation to systemic levels of tumor necrosis factor (TNF) and IL-6 (interleukin-6) were examined in a rat model of experimental cancer cachexia employing the methylcholanthrene (MCA) sarcoma. Fischer 344 rats, implanted with biotelemeters for measuring temperature and activity, were implanted subdermally with tumor tissue fragments. Ad libitum-fed and pair-fed controls were sham incised. Bioassays for TNF and IL-6 were performed on serial plasma samples, obtained via jugular vein at 3- to 6-day intervals throughout the experimental period. Tumor growth induced significant anorexia, weight loss, and a decline in motor activity corresponding to an increase in mean plasma IL-6 levels, independent of reduced food intake or weight loss alone as shown in pair-fed controls. A significant lowering of body temperature then developed, followed by a two- to threefold increase in water consumption. The patterns of weight loss and temperature reduction differed in rate and degree from those seen with pair feeding.

Human IL-1 receptor antagonist partially suppresses LPS fever but not plasma levels of IL-6 in Fischer rats

A human recombinant interleukin-1 receptor antagonist (IL-1ra) recognizes the two known IL-1 receptors and blocks the binding and many biological effects of both IL-1 alpha and IL-1 beta. The effectiveness of IL-1ra in modifying the fever and plasma IL-6 responses elicited by lipopolysaccharide (LPS) in vivo was tested in Fischer 344 rats. Animals that received IL-1ra 0.5 mg/kg intraperitoneally followed 10 min later by 10 micrograms/kg of LPS displayed significantly lower mean fever responses 2-4 h after injection than rats that received vehicle and LPS (0.48 +/- 0.13 vs. 0.95 +/- 0.16 degrees C, P = 0.016). Plasma levels of IL-6 at 4 h after injection were not different in IL-1ra-treated rats compared with controls (407,725 vs. 729,169 U/ml). Based on our previous finding that preadministration of antiserum to IL-1 beta markedly suppressed plasma IL-6 after LPS, and recent evidence that molar excesses of IL-1ra blocked IL-1-induced circulating IL-6 levels, the possibility that IL-1 is responsible for the induction of bioactive IL-6 during inflammation cannot be ruled out. Similarly, the inability of the IL-1ra to completely suppress the febrile responses of rats to LPS in the present study may be dose related. Alternatively, the induction of bioactive IL-6 by IL-1 in the rat may be mediated primarily through some receptor other than the type I (e.g., the type II receptor).

Management of the oral and maxillofacial surgery patient on anabolic steroids

Recent Food and Drug Administration estimates indicate that the anabolic steroid market has reached the $100 million level. Although the news media report steroid-related deaths, there is little in the medical literature communicating the clinical implications concerning these drugs. Electrolyte disturbances, coagulopathies, hypertension, and dysrhythmias are a few of the potential side effects. The pharmacology and pathophysiology of anabolic steroids are presented with a discussion of the anesthetic and surgical concerns for the patient undergoing oral and maxillofacial surgery.

Direct Observation of Dissociated Dislocations in Garnet

Dislocation core structures in garnet [grossularite (Ca(2.9)Fe(II)(0.1))(Al(1.9)Fe(III)(0.1)Si(3.0)O(12)] have been examined with near atomic resolution transmission electron microscopy. Dissociated dislocations have been observed as parallel a/4<111> partial dislocations that are separated by stacking faults. The partial dislocations have narrow cores ( approximately 3 burgers vectors), and the stacking fault zone between the narrow partial dislocations is apparently a low-energy configuration that results from the occupancy of previously unfilled dodecahedral and tetrahedral sites. Previous studies of garnet dislocations suggested that dissociation involves departures from garnet stoichiometry (that is, trace amounts of impurities), but evidence of detectable amounts of impurities has not been found even in the highest resolution images. These results have implications for mantle mineral rheology and transformations as well as for ceramics of material science interest.

Simple reagent modification of Technicon H6010C that permits processing of uraemic samples

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Use of helium-oxygen to examine the effect of cold acclimation on the summit metabolism of a marsupial, Dasyuroides byrnei

To determine whether marsupial mammals increase their metabolic capabilities during cold acclimation, the metabolism of both warm and cold acclimated Dasyuroides byrnei was examined by exposure to cold in a helium-oxygen atmosphere. Mean values of heat production and conductance were significantly higher in a helium-oxygen atmosphere than in air. Body temperature did not change until metabolic capacity was exhausted. Both cold and warm acclimated groups could maintain a metabolic scope of 10-11 times the basal or standard level for this species. Such a metabolic scope is much higher than levels recorded for placental mammals. At very low ambient temperatures cold acclimated D. byrnei could sustain a high level of heat production longer than could warm acclimated animals. While there are some similarities between marsupial mammals and placental mammals in their responses to cold acclimation, an increase in maximum metabolism, as reported for placentals, does not seem to occur in marsupials.

Burns and pregnancy

Pregnancy does not predispose to thermal injuries. Most burns are minor, and erythema usually subsides within 24 hours during the outpatient therapy. Severe burns during pregnancy are rare but alarming events. Care should be provided at a regional facility with expert burn care and fetal monitoring. Attempts should be undertaken during maternal transport to avoid hypovolemia, hypotension, and hypoxia. The wound should be covered with sterile dressings to prevent further contamination. Maternal and fetal survival is directly related to the extent of the body surface injury. When maternal injury is lethal, fetal survival is very unlikely because of sudden in-utero death or complications from prematurity following spontaneous labor. Complications to be considered during the emergent and acute phases of recovery include fluid and electrolyte imbalance, respiratory difficulties, systemic and wound infection, inadequate nutrition, and emotional disturbances. Therapy should be directed to saving the mother. Whether fetal well being is compromised by the burn and resultant therapy is difficult to determine from prior published reports. Periodic ultrasonic examination and biophysical testing of the fetus are recommended. If conditions are considered unfavorable to meet fetal circulatory and oxygen demands, prompt delivery during the late second and third trimesters has been advocated if the mother's burn covers 50 per cent or more of the surface area. If the patient has instead recovered satisfactorily and there has been no evidence of fetal jeopardy or premature labor within the first week following the burn injury, the eventual delivery of a healthy-appearing, term-sized fetus is quite likely.

Serum pyridoxal, folate, and vitamin B12 levels in institutionalized epileptics

Serum pyridoxal, folate, and vitamin B12 concentrations were measured in 68 institutionalized patients with severe epilepsy. Twenty-five patients had a reduced level of pyridoxal and thirty-three a reduced level of folate. There was no instance of a low serum vitamin B12 although in three patients the levels were found to be abnormally high. Fifteen patients had both a low serum pyridoxal and a low serum folate but there was no significant correlation. All patients had a normal hemoglobin concentration and a normal mean corpuscular volume. There was no close relationship between reduced serum vitamin levels and single or groups of anticonvulsant agents, although the size of the groups was too small to permit a detailed study.