April 1995 Growth, Development, and Nutrition A719

MEASUREMENT OF UNABSORBED DIETARY CARBOHYDRATE AND THEIR FERMENTATION PRODUCTS FOLLOWING THE INGESTION OF 13C CARBOHYDRATE (CHO). F.Briet, B.Flouri6, L.Achour, M.Maurel, J.C.Ramband, B.Messing. 1NSERM U290, H6pital S t Lazare, Paris.

Dietary carbohydrate (CHO) which are not absorbed in the small intestine are fermented in the colon, producing gases (CO2, Ha), shart-chain fatty acids and bacterial mass. Currently, there is no available method to determine precisely the amount of unabsorbed dietary CHO and their fermentation products excreted in stools. In this work. we developed a clinical test for assessing the malabsorption of dietary CHO together with their fermenetation products through the digestive tract. For this purpose, patients with a malabsorption syndrome were given orally t~C naturally enriched CHO and we measured the excretion of~3C in stools and ~3CO2 in breath. Methods: Seven short bowel patients (lenght 69±40 cm, m±SD) with (n=5) or without (n=2) remaining colon in continuity ingested a meal after an overnight fast (793 Kcal, 17/26/57% of Protein/Fat/CHO) containing t3C naturally e~iched CHO in a form of corn starch (257 ~tmol of t3C) and sugar cane (233 p.mol off'C) and carmin red as a recovery marker. Patients consumed a low ~3C diet and stools were collected one day before and 3 days after the meal. Breath samples were collected and VCO~ was measured using indirect calorimetry hourly for 6h after test meal ingestion. In breath, in the premeal and red postmeal stools, ~3C enrichment was measured by an Isotope Ratio Mass Spectrometer. Fecal and breath ~3C enrichment was corrected for the basal premeal value. Results: (mean±SD, range in brackets~ n=7)

Excess fecal output % of ingested dose % of ingested dose of 13C (tamol) recovered in stools exhaled in breath/6h

115±88 22~17 30±8 (6-245) (1-50) (16-40)

The excess fecal output of 13C was inversely related to the ~3CO 2 exhaled in breath for 6h following the ingestion of test me~ (Spearman correlation Rho=-0.96, p<0.02). Conclusion: Fecal measurement of ~3C from dietary CHO is an useful tool for assessing together the fate of CHO and their fermentation products through the digestive tract of patients with malabsorption syndrome. In addition, our preliminary data show that a 6h breath J3CO2 test could avoid stool collection.

PLASMA AMINO ACID CONCENTRATIONS IN NORMAL VOLUNTEERS BEFORE AND AFTER TPN AND FOLLOWING ENTERAL REFEEDING: AL Buchman, A Moukarze], JD Kopple, SR Vijayaraghavan, ME Ament. Sec of Gastro, Baylor College of Medicine, Houston, TX, Div of Peds Gastro, Maimonides Med Ctr, Brooklyn, NY, Div of Nephrology and Hypertension, Harbor UCLA Med Ctr, Torrance, and Div ofPeds Gastro, UCLA Med Ctr, Los Angeles, CA.

8 normal volunteers (4M, 4F) aged 18-34 yrs received TPN followed by enteral tube feeding as an exclusive source of nutrition. TPN contained a balance free amino acid solution (Travasol, Baxter, Deerfield, IL). Blood samples were obtained via peripheral venipuncture in the arm opposite the PICC used for TPN at baseline, after 7d and 14d of TPN and after 5d of enteral refeeding. The subjects were prospectively randomized to receive a std enteral formula (Osmolite, Ross, Columbus, OH) or a free amino acid/peptide-based formula supplemented with gin and arg (Alitra Q, Ross). Plasma amino acid concentrations were analyzed by ion exchange chromatography.

Subjects received a mean of 116% and 102% of REE during TPN and enteral refeeding respectively. There was no significant correlation between any plasma amino acid concentration and the amount infused either intravenously or enterally in the 24 brs prior to testing. At day 7 a significant increases were seen in his (76.8 + 3.6 vs 96.0 + 4.8 taM, p=0.002), fie (77.5 + 9.1 vs 104.8 + 2.8 gM, p=0.0003), met ( 29.5 + 1.9 vs 50.0 + 4.6 p.M, p=0.0001), phe (57.8 + 3.1 vs 88.8 +. 4~0 taM, p=0.0001), ala (381.8 + 65.2 vs 527.7 + 41 taM, p=0.03), arg (82.2 + 6.0 vs 149.8 + 12.9 taM, p=0.0002), gly (221.5 + 21.4 vs 362.0 + 40.2 taM, p=0.000 !), orn (853 + 5.6 vs 102.7 + 4.7 [aM, p=0.04), and ser (126.5 + 7.2 vs 161.0 + 22.5 ttM, p=0.05). Tyr was significantly decreased (65.8 + 6.7 vs 42.2 + 3.0 ~M, p=0.0002). By Day 14 all amino concentrations (except nonsignificant decreases in tyr, ala, gin, gly, orn, pro, and ser) tended to increase with significant increases seen for his ( 108.0 _.+ 35 taM, p=0.04), ile (I 17.8 + 67 taM, p=0.04). No significant difference in any plasma amino acid concentration was seen between subjects who received Osmolite vs Alitra Q. At Day 20 plasma amino acid concentrations between subjects who received Osmolite vs those who received Alitra Q were similar except for arg which was significantly greater in the AIitra Q group (100.7 + 1.8 vs 76.7 + 3.8 p.M, p=0.005) and gly which was significantly greater in the Osmolite group (238.7 + 11.9 vs 187.7 + 11.3 taM, p--'0.04). The formulas contained more of these respective amino acids than the other.

Our data suggests of either TPN or amino acid-supplemented enteral formulas are associated with significant changes in plasma amino acid concentrations. Tyr may be the limiting amino acid in TPN. Further study is indicated to determine if physiologic consequences result from the long term alteration of plasma amino acid concentrations from nutritional support and whether current amino acid formulations are appropriate. Partially funded by Ross Labs and USPHS RR00865.

• REGULATION OF THE DEVELOPMENT OF INTERSTITIAL CELLS OF CAJAL IN THE GASTROINTESTINAL TRACT. A.J. Bums. S. Torihashi, S.C. Harney, K.M. Sanders and S.M. Ward. Department of Physiology, University of Nevada, Reho;HV 89557.

The development of the network of interstitial cells of Cajal (ICs)~n the small intestine of the mouse depends upon the function of c-k/t protein, a receptor tyrosine kinase. We have pre~iously Shown that an antibody for c-kit protein labels interstitial cells in the small bowel and colon of mice (Torihashi et al., Cell Tiss Res, In press). Using an anti-c-kit antibody to identify ICs and intracellular electrophysiological recording techniques, we have compared the development of ICs and electrical activity in the stomachs and small bowels of normal (+/+), WAVv mice (spontaneous mutation in c- kit) and S1/SI d (spontaneous mutant in the ligand for c-kit, stem cell factor). Immunohistoohemistry using whole mounts from the gastric antrums of +/+, W/W v and SI/SP mice showed comparable distributions of ICs, and the development of the network of ICs near the myenterie plexus region (days 5- 30 after birth) was similar in each group of animals. Electrical recordings from the circular muscle layers from each group of animals were similar. Slow wave frequency averaged 5.15 ± 1 rain "1, 5.28 ± 1 rain "~ and 6.0 • 1 rain -~ and slow wave amplitude averaged 26.3 ± 4 mV, 16.3 ± 4 mV and 15.5 ± 3 mV for +/% W/W v and sI/SP animals, respectively. Membrane potentials were slightly more depolarized in muscles of W/W v and SI/SI d animals (-71 =L 2 mV for +/+ versus -62 ± 2 mV for W/W v and -58 ± 2 mV for SI/SP). Small bowel muscles were also slightly depolarized (-71 ± 2 mV for +/+ versus -62 ± 2 mV for W/WVand -53 ± 2 mV for SI/S1 a) and slow wave activity was absent in WAV v and SI/SP animals. The IC network and total number of ICs per unit area were compromised in muscles from the small intestine. However in the antrum, the distribution of interstitial cells in the myentefic region of +/+ and W/W v was'~imilar. These data suggest that different growth factors may regulate IC development in different regions of the gastrointestinal tract. (Supported by DK41315)

D O P R E S S U R E S G E N E R A T E D D U R I N G S W A L L O W I N G

CHANGE W I T H AGE? J.A. CASTELL, J. BARRETT, R. M. G I D E O N , D . O . CASTELL. The Graduate Hospital, Philadelphia. PA

It is generally excepted that dysphagia is a symptom seen more commonly in the elderly. With the increasing use of manometry in the evaluation of dysphagia we feel it is important to understand what Pressure changes might occur solely as a result of age and to develop normal values in an elderly population. We compared UES/P manometric parameters for 17 healthy volunteers (11M,6F) with a mean age of 74.5 (range 65-91) to those for 17 healthy volunteers (SM, gF) mean age of 25.2 (range 18-38). Each subject was evaluated for resting UES pressure and during six swallows each of 5 ml water, 1 T pudding and 1/4 Lorna Doone cookie. R e s u l t s : (IDES resting pressure=UESP, UES residual pressure=UESR, relaxation duration=UESD, maximum P pressure=PMAX, contraction duration=PDUR, prepharyngeal pressure elevation amplitude and duration = PPAMP, PPDUR, onset of contraction to relaxation=COORD) Mean Values WET COOKIE PUDDING

young old p young I old p young old p UESP mmHg ,,, 97 50 .001

' U E S R m m ~ . -2.1" 4.2 .001 -5.1" 2.8 .004 L4* 5.6 NS UESD msec 600 531 ms 526 439 NS 203 194 NS PMAX mnd~g 13:$ 174 NS 157 191 NS 138 198 .85 PDUR msec 398 506 .005 424 563 ~ .001 433 534 .02 PPAMP i 16" 18" NS 23" 35" NS 15" 27" .02

PPDUR msec 123" 272 .01 195" 185 NS 223" 196 NS COORD mse¢ -275' -220 NS -169" -123 NS -207" -184 NS

P < . 0 5 A N O V A f o r f o o d t y p e s w i t h i n a g e

C o n c l u s i o n s : LIES loses tone with age. Apparent changes in pharyngeal function are probably a result of loss of compliance in the UES as is loss of seusivitity to c h a n g e s in food type. Manometric values for patients over 65 should be compared to an age matched normal population.