Taste and smell perception in depression.
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Biomedical subjects
Publications and source records attributed to R G Settle.
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Energy expenditure of four subjects was measured by the doubly-labelled-water (2H2 18O) method to determine if energy expenditure could be determined over short periods. Three subjects were studied while they performed 8 h of heavy exercise in a laboratory environment. Urine and blood samples were taken before and after exercise. Estimated energy expended during 8 h of high-intensity exercise (55% VO2 max) for three subjects was 757 +/- 118 kcal/h by the doubly-labelled-water method using urine and a two-point calculation, which compared favorably with 735 +/- 82 kcal/h obtained by respiratory gas exchange. For the fourth subject, daytime, nighttime, and daily energy expenditure was calculated by both the two-pair method and decay-curve analysis of urine and saliva samples collected in the morning and at night. Daytime and nighttime energy expenditures differed significantly (p less than 0.05).
There is no accurate noninvasive method for differentiating between partial-thickness and full-thickness cutaneous burn wounds. Full-thickness burns (FTB) result in slower resorption of wound edema than partial thickness burns (PTB). Since proton NMR parameters, particularly the T1 relaxation time, correlate with tissue water content (TWC), the present study determined whether proton NMR could distinguish PTB from FTB. An area of upper dorsum (approximately 15% BSA) of 35 adult rats was immersed in boiling water for either 3 sec (PTB) or 10 sec (FTB). In 10 control rats, the same area was immersed in room temperature water. Rats were sacrificed at either 3 or 48 hr after burn, and skin samples were analyzed to determine spin-lattice (T1) and spin-spin (T2) relaxation times. TWC was then measured gravimetrically by desiccation. Both T1 and T2 times significantly correlated with TWC (T1: r = 0.74, P less than 0.0001; T2: r = 0.75; P less than 0.0001). Both PTB and FTB resulted in significant elevations of T1, T2, and TWC 3 hr after injury (P less than 0.001). At 48 hr postburn the T1, T2, and TWC of the PTB group had decreased to control values (P less than 0.05), while all FTB parameters remained significantly elevated as compared to both the control and the 48-hr PTB parameters (P less than 0.001). In vitro NMR measurements distinguish PTB from FTB in this rat model within 48 hr. These data provide a basis for investigating in vitro NMR techniques for the noninvasive assessment of burn wound depth.
In Experiment 1, a taste quality fractionation procedure was used to establish the degree to which sour and non-sour taste sensations are elicited by six concentrations of each of seven acids: citric, hydrochloric, sulfuric, lactic, malic, phosphoric and tartaric. In general, the acids differed significantly in their ability to elicit sour, salty and bitter sensations, with sulfuric and hydrochloric acids producing the smallest proportions of perceived sourness. Bitterness was found to be the largest non-sour sensation produced, followed by saltiness. The perceived taste qualities of the acids were stable across a wide range of concentrations. In Experiment 2 the extent to which the vapors of these test acids produce detectable intranasal non-gustatory sensations at concentration levels used in many human taste experiments was examined. All acids induced clear intranasal sensations at concentration levels used in some suprathreshold taste paradigms. The results suggest that a number of measures of sour taste sensation may be confounded by non-sour chemosensory factors, including intranasal stimulation.
Eight 15N-labeled nonessential amino acids plus 15NH4Cl were administered over a 10-h period to four healthy adult males using a primed-constant dosage regimen. The amount of 15N excreted in the urine and the urinary ammonia, hippuric acid and plasma alanine 15N enrichments were measured. There was a high degree of consistency across subjects in the ordering of the nine compounds based on the fraction of 15N excreted (Kendall coefficient of concordance W = 0.83, P less than 0.01). Protein synthesis rates were calculated from the urinary ammonia plateau enrichment and the cumulative excretion of 15N. Glycine was one of the few amino acids that gave similar values by both methods.
Protein and energy metabolism were investigated in acutely septic rats. Rats were made septic by cecal puncture and ligation. For the next 24 h they were given one of five parenteral formulations differing only in the nonprotein calorie source. The five calorie sources were 1) glucose, 2) long-chain triglycerides (LCT), 3) a 27:73 mixture of medium- and long-chain triglycerides (M/LCT), 4) a 50:50 mixture of glucose plus LCT, and 5) a 50:50 mixture of glucose plus the M/LCT mixture. The formulations also contained amino acids at a calorie:ratio of 165:1. The results were that N retention was greater with the glucose plus LCT mixture than with glucose alone. With this mixture, N retention increased as calorie intake increased, whereas with glucose, N retention plateaued. In spite of the high glucose load given to the glucose-only groups, there was a significant reduction in endogenous fat in peripheral depots. Lipid loss was least with the glucose plus LCT combination. The M/LCT mixture given alone or with glucose resulted in significantly lower survival rates.
The effect of the addition of pectin to an elemental diet on the healing of experimental colonic anastomoses was investigated. Transection and anastomosis of the ascending colon and feeding gastrostomy were performed in 24 Sprague-Dawley rats. All rats then received an elemental diet, and 12 of them had 1% (w/v) citrus pectin added to their diet. On the seventh postoperative day, animals that received pectin-supplemented diets had significantly greater bursting pressures at the anastomoses (266 versus 234 mm Hg, p less than 0.04) and significantly lower colonic mucosal pH (6.2 versus 6.8, p less than 0.001) than animals that received the elemental diet only. The colons from animals fed pectin also had significantly higher hydroxyproline content at the anastomosis than those of the control animals (46.6 versus 40.7 micrograms hydroxyproline nitrogen/mg tissue nitrogen, p less than 0.05). The decreased intracolonic pH is consistent with the hypothesis that improved healing is a local effect mediated by the presence of short-chain fatty acids resulting from the fermentation of pectin.
The effects of an intracolonic infusion of short-chain fatty acids (SCFA) on the healing of colonic anastomosis in the rat were investigated. Thirty-three Sprague-Dawley rats underwent transection and anastomosis of the descending colon and transection and diversion of the ascending colon. The proximal limb of the ascending colon was exteriorized as an end colostomy, and the distal (defunctionalized) limb was cannulated for continuous infusion. Rats received either no infusion (N = 11) or an infusion of either electrolytes (N = 11) or SCFA (acetate, propionate, and butyrate; N = 11) into the defunctionalized colonic segment. On the sixth postoperative day bursting pressure (BP) and bowel wall tension (BWT) were determined. The occurrence of spontaneous anastomotic dehiscence was significantly less for the SCFA group (0/11) compared with the no infusion group (5/11, p less than 0.01). The anastomotic suture line burst in significantly fewer colons from the SCFA group (1/11) than either the electrolyte infusion (8/11, p less than 0.003) or the no infusion (6/6, p less than 0.001) groups. BP and BWT were significantly higher for the SCFA group (BP: 147 +/- 10 mm Hg; BWT: 59 +/- 1.0 dyne 10(3)/cm) than for either the electrolyte (BP: 99 +/- 30 mm Hg, p less than 0.002; BWT: 45 +/- 19, p less than 0.03) or no infusion (BP: 111 +/- 42, p less than 0.02; BWT 36 +/- 15, p less than 0.007) groups. The results of this study indicate that intracolonic infusion of SCFA resulted in significantly stronger colonic anastomosis in the rat.
Appendicitis was induced in six New Zealand white rabbits. The appendices from these animals had significantly higher spin-lattice relaxation times, T1, as determined in vitro by nuclear magnetic resonance (NMR) (10 controls vs 6 experimentals, 413 +/- 23 vs 455 +/- 41, X +/- SD, P less than (0.02). T1 correlated significantly with the water content of the appendiceal tissue (P less than 0.001). These findings suggest that in vivo NMR imaging techniques weighted on T1 might be able to identify human appendicitis noninvasively by detecting localized edema.
To determine if NMR techniques might be used to detect hepatic steatosis secondary to protein malnutrition, the T1 and T2 relaxation times of liver tissue from rats subjected to long-term protein malnutrition were measured in vitro. The liver tissue from rats fed a protein-deficient rat chow (PD) for 37 days (N = 9) was characterized by increased proportion of fat (P less than 0.001) but decreased water and nitrogen contents (P less than 0.001) relative to controls (N = 9). Mean T1 times were significantly shorter and T2 times significantly longer in liver tissue from protein-depleted animals (P less than 0.001). There was no overlap of T2 times between the protein-depleted and control animals. The consistent changes in T2 that occur with fatty infiltration of the liver should be detectable by current NMR imagers.
To ascertain the generality of a sex difference noted in odor identification ability, the University of Pennsylvania Smell Identification Test (UPSIT) was administered to four groups of subjects: Black Americans (n = 438), White Americans (n = 1559), Korean Americans (n = 106), and Native Japanese (n = 308). The women of all four groups outperformed the men to the same relative degree. The Korean American group performed better than the Black and White American groups, which, in turn, outperformed the Native Japanese. Analyses of the proportions of subjects correctly answering each of the test items revealed considerable similarity of relative item difficulty among the subject groups. Taken together, these data suggest that sex differences in odor identification ability are probably not due to ethnic or cultural factors, per se.
To determine the effect of anesthetics on liver relaxation times in rat, two experiments were performed. In the first experiment, normal and protein-depleted rats underwent total hepatectomy under ether anesthesia or following decapitation. In the second experiment, livers were excised from normal rats under ketamine or pentobarbital anesthesia, or following decapitation. Hepatic T1 and T2 were measured for all animals using a RADX 10 MHz spin analyzer. Ketamine produced T1 values significantly different from decapitation. Ketamine, pentobarbital, and ether in normal animals all produced T2 values significantly different from decapitation. It is apparent that anesthetization of rats prior to in vitro measurement of hepatic relaxation times is not equivalent to decapitation; nor are the anesthetics examined equivalent to one another.
The present study determined whether in vitro nuclear magnetic resonance could be used to assess experimentally induced colitis in rats. Acute colitis was induced in 6 Sprague-Dawley rats by acetic acid enema, while 6 control animals received saline enemas. All animals were sacrificed 24 hours post-enema, and NMR relaxation times, T1 and T2, of colonic samples were determined on a 10 MHz spin analyzer (RADX, Houston, TX). Colonic water content was determined on the same samples by desiccation. Colitis animals showed significantly higher T1 and T2 relaxation times and tissue water content than controls. T1 and T2 times correlated significantly with tissue water content. Twelve additional animals were studied histologically, six of which received acetic acid enemas and showed extensive transmural colitis. Our results suggest that in vivo proton NMR might be a useful means of non-invasively assessing the degree of colonic inflammation.
The impact of a multidisciplinary Nutritional Support Service (NSS) on the reduction of complication was evaluated in 78 consecutive patients who received total parenteral nutrition (TPN) on the same VA surgical service. Patients were placed into one of three groups (pre-NSS, transition-NSS, post-NSS) based on the evolution of the NSS. A significant reduction in catheter sepsis was observed and was attributable to the establishment of an NSS, specifically, a nurse specialist and protocols for catheter insertion and care.
Protein and fat metabolism were studied in fed and protein-depleted rats. The rats were given one of three isocaloric, isonitrogenous nutrient mixes parenterally. The nutritional regimens differed in the source of nonprotein calories: i) glucose, ii) an emulsion containing long-chain fatty acid triglyceride esters (LCT), and iii) an emulsion containing both LCTs and medium-chain fatty acid triglycerides (MCT). Nitrogen balance, protein synthesis and breakdown, fat deposition in the liver, and the periuterine fat pads were measured using [15N]glycine as the tracer for the protein metabolism and deuterium for the lipid studies. Results are as follows. i) Nitrogen retention and protein synthesis were greater in the fed rats treated with glucose than with LCT. ii) Nitrogen fluxes were lower with LCT than with glucose. iii) Extensive lipogenesis in the liver was only found with the glucose-treated rats. iv) None of the caloric regimens promoted lipogenesis in the periuterine fat pads. v) With the two lipid-containing regimens there was a relative depletion of the depot fat in the periuterine fat pads relative to their glucose-treated counterparts. v) Although the MCT-containing emulsion did not cause hepatomegaly, its apparent caloric effectiveness was lower than that of either glucose or LCT. vi) Chain elongation is not a major pathway for MCT metabolism in parenterally nourished rats.
UNLABELLED: The whole-body flux and protein-synthesis rates were determined in two groups of adult males aged 20-30 years who were matched for height and weight. [15N]Glycine was used as a tracer. Flux and synthesis rates were calculated from the urinary ammonia 15N excretion enrichment. Group I consisted of international competition level oarsmen, while Group II engaged in no exercise program. Measurement of the urinary nitrogen excretion rate showed that the oarsmen excreted more than twice as much nitrogen as the control group (P less than 0.05). RESULTS: flux and synthesis were 21.3 +/- 3.2 gN/9 hr and 188.7 +/- 59.9 g protein/day for the oarsmen and 16.4 +/- 2.1 g N/9 hr and 201.7 +/- 33.0 g protein/day for the controls. Data are +/- 1 SD for the eight oarsmen and eight controls. The flux values were different at the P less than 0.05 level. We concluded that (i) an exercise program does not lead to an increase in the basal protein turnover rate in adequately nourished individuals.
The influence of intertrial interval durations ranging from 7 to 30 s upon sucrose detection thresholds of sixteen subjects was investigated by means of a modified staircase procedure with intertrial rinses. In addition, the influence of the sex of the subject was examined. Neither the intertrial interval nor the sex of the subject significantly affected sucrose detection thresholds. The results suggest that, in sucrose detection threshold studies using the present procedure, one can employ intertrial intervals as short at 7 s without significantly affecting the threshold value.
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