Resumption Of Feeding Research Articles

Anesthesia in the breast feeding period. Excretion of anesthetic agents and adjuvants into breast milk and potential pharmacological side-effects on the suckling infant

Whenever an anesthetic is needed during the breast feeding period, potential pharmacological side-effects imposed on the infant by any kind of anesthetic agent used during both general and regional anesthesia are in contrast to the potential beneficial effects of breast feeding for the infant and the mother. Despite an increasing knowledge and understanding of the mechanisms of excretion of drugs and their metabolites through breast milk, information about most anesthetic drugs are still either inconclusive or contradictory. Often it is impossible to decide whether a certain substance that is potentially excreted through breast milk might be harmless or harmful for the breast-fed infant. In addition to that only few anesthetic agents and drugs used in conjunction with an anesthetic are officially approved for use during pregnancy and the period of breast feeding and for medico-legal reasons pharmaceutical companies generally advise against the use of any of those drugs during this period. However, based on the knowledge of pharmacological properties of commonly used anesthetic agents it is reasonable to assume that continuing breast feeding in the immediate postoperative period after a single anesthetic can be considered safe for the infant since no adverse effects caused by or secondary to the single use of those drugs can be expected. Provided there is a careful choice of anesthetic drugs, there is no need to consider that a single general or regional anesthetic is an indication to stop breast feeding. Even planned elective surgical procedures do not need to be postponed. No scientifically based interval between surgery under general or regional anesthesia and resumption of breast feeding can be recommended. Instead current opinion is that breast feeding can be resumed as soon as the mother feels physically and mentally capable to do so.

Effects of hypothyroidism and withholding of feed on plasma lipid concentrations, concentration and composition of very-low-density lipoprotein, and plasma lipase activity in horses.

To evaluate selected concentrations of blood lipids and lipase activities in euthyroid and hypothyroid horses deprived of feed for 96 hours. 4 healthy adult mares and 4 thyroidectomized adult mares. Horses were deprived of feed for 96 hours. Blood samples were collected at 24-hour intervals and analyzed to determine concentrations of non-esterified fatty acid (NEFA), triglyceride (TG), total cholesterol (TC), and very-low-density lipoprotein (VLDL) as well as composition of VLDL. Plasma lipase activities were measured after feed was withheld for 96 hours and 12 days after resumption of feeding. Time significantly affected plasma NEFA, VLDL, TG, and TC concentrations in both groups of horses. During the 96-hour period, mean plasma concentrations of NEFA and VLDL increased 10-fold in euthyroid horses and increased 5-fold and 9-fold, respectively, in hypothyroid horses. Mean plasma TG concentrations increased 8-fold in both groups, and plasma TC concentrations significantly increased by 33 and 30%, respectively. Composition of VLDL was significantly affected by feed deprivation in euthyroid horses. Activities of lipoprotein lipase and hepatic lipase were significantly higher in feed-deprived horses. Activity of hepatic lipase was significantly lower in hypothyroid horses than in euthyroid horses. Hypothyroidism did not significantly alter the magnitude of the response of blood lipids to feed deprivation. Thyroid hormones may reduce variability in blood lipid concentrations but do not determine susceptibility to hyperlipemia. Hypothyroidism does not appear to be a factor in the pathogenesis of hyperlipemia in horses.

Changes in the expression of TGFβ-isoforms in the anterior pituitary during withdrawal and resumption of feeding in hens

Our goal was to determine whether TGFβ-isoforms were involved in the remodeling of the pituitary cell population which occurred by regulation of feeding. The current study examined whether TGFβ-isoforms were produced in the anterior pituitary, and the mRNA expression of TGFβ-isoforms changed during withdrawal and resumption of feeding. White Leghorn laying hens were subjected to feed withdrawal for 4 days with a resumption of feeding thereafter. The anterior pituitary tissues were collected from hens of pretreatment (PT), 3 days after feed withdrawal (3DFW), 1 and 5 days after the resumption of feeding (1DRF and 5DRF, respectively), and on the day of resumption of egg-laying (RL). They were processed for semi-quantification of TGFβ2, β3, and β4 mRNA expressions by reverse transcription-polymerase chain reaction (RT-PCR) and for immunocytochemistry for TGFβ3. TGFβ2, TGFβ3, and TGFβ4 mRNA expression with a product size of 269, 236, and 163 bp, respectively, was observed in the anterior pituitaries in all groups of hens. Although the expression of TGFβ2 and TGFβ4 mRNA did not show any significant change, that of TGFβ3 mRNA significantly declined in the 1DRF hens and recovered by the resumption of laying. Immunostaining revealed that TGFβ3 was located in the cytoplasm of glandular cells with granule forms in all groups of hens. The ovarian and oviductal weights sharply declined in the 3DFW and 1DRF groups, followed by a full recovery in the RL hens. These results indicate that TGFβ2, β3, and β4 were expressed in the chicken anterior pituitary, and TGFβ3 mRNA expression was changed in correlation with the regulation of feeding, suggesting that this isoform may play a significant role in the regulation of the glandular cell population and/or differentiation.

Total Parenteral Nutrition in Bone Marrow Transplant: What Is the Appropriate Energy Level?

Objectives: Total parenteral nutrition (TPN), recommended during bone-marrow transplant (BMT), is often withheld following complications. We aim to determine the effective amount of energy supplied and its short-term effects in children requiring BMT. Methods: Twenty children (11 males, 9 females, mean age 8 years, range 1–18 years) receiving 13 allogenic and 7 autologous BMT for malignant (13) and nonmalignant (7) diseases, were retrospectively evaluated for energy/protein intakes, weight changes, time to engraftment and on TPN, occurrence of complications, and metabolic abnormalities. Results: Each child received approximately 72% of the prescribed calories, an average of 0.87 ± 0.2 × basal-metabolic rate, 1.14 ± 0.4 g protein/kg/day, and 176 ± 34:1 nonprotein calories:nitrogen ratio. Body weight improved during the 35 days (range 14–62) of TPN, with loss thereafter. Engraftment occurred in 20 ± 7.5 days. Caloric intake and time to engraftment were related (p = 0.002). Ten central-venous-line and 12 gastrointestinal infections occurred. Among laboratory abnormalities, liver function tests resulted temporarily altered in 10 patients, and permanently in 1 child with cholestasis. Eight children developed graft-versus-host disease. Five died of cancer. Conclusions: The energy supplied with TPN in BMT is less than expected and approximately covers the BMR with mixed effects. Energy intake needs to be calibrated during TPN and adjusted during feeding resumption to expedite recovery.

Relationships between larval nutritional experience, larval growth rates, juvenile growth rates, and juvenile feeding rates in the prosobranch gastropod Crepidula fornicata

Planktonic larvae experiencing short periods of starvation or reduced food supply often grow and develop more slowly, have poor survival, fail to metamorphose, metamorphose at smaller sizes, or grow slowly as juveniles. In this study, we examined the impact of short periods of food limitation at various stages of larval development on larval and juvenile growth in Crepidula fornicata. In addition, we considered whether juveniles that were stressed as larvae grew poorly because of reduced rates of food collection due to impaired gill function. For 5 experiments, larvae were either starved for several days beginning within 12 h of hatching or were starved for the same number of days following 1 or more days of feeding at full ration (cells of the naked flagellate Isochrysis galbana, clone T-ISO, at 18×10 4 cells ml −1). In one experiment, larvae were transferred for 2 or 4 days to seawater with extremely low phytoplankton concentration (1×10 4 cells ml −1). In all experiments, larvae were returned to full ration following treatment. Control larvae were fed full ration from hatching to metamorphosis. When larvae reached shell lengths of about 900 μm they were induced to metamorphose and then reared individually at full ration in glass bowls, with phytoplankton suspension replenished daily. Larval and juvenile growth rates were determined by measuring changes in shell length (longest dimension) over time. Juvenile feeding rates were determined by monitoring changes in phytoplankton concentration over 2–3 h at the end of the growth rate determinations. In general, larval growth rates for the first 2 days after the resumption of feeding were inversely proportional to the length of time that larvae were starved. However, larval growth rates ultimately recovered to control levels in most treatments. Starving the larvae caused a significant reduction in initial juvenile growth rates (first 3–4 days post-metamorphosis) in most experiments even when larval growth rates had recovered to control levels prior to metamorphosis. Juvenile growth rates were not significantly reduced when larvae were subjected to reduced food availability (1×10 4 cells ml −1), even for treatments in which larval growth rates were compromised. Mean weight-specific filtration rates for juveniles were significantly reduced ( p<0.05) following larval feeding experience in only one or possibly 2 of the 4 experiments conducted. Our data suggest that although larvae of C. fornicata may fully recover from early nutritional stress, the resulting juveniles may exhibit poor initial growth due to impaired gill function, reduced digestive capability, or reduced assimilation efficiency.

Effects of Early Skip-a-Day Feed Removal on Broiler Live Performance and Carcass Yield

Programs that limit early growth of broilers are widely used to reduce mortality and culling and to improve feed conversion. Skip-a-day feed removal is a technique for limiting early growth and has not been extensively examined for broilers. This technique may be more easily implemented than other commonly used programs. Broilers were subjected to one of the following regimens: provided feed ad libitum to 54 d of age (AL); ad libitum except for 24-h removal periods at 8 and 10 d of age (R2); 24-h removal periods at 8, 10, 12, and 14 d of age (R4); or 24-h removal periods at 8, 10, 12, 14, 16, and 18 d of age (R6). Body weights at the end of feed removal were reduced 29, 35, and 41% by R2, R4 and R6 treatments, respectively, when compared with the AL treatment for the same periods. Average daily gains on R4 and R6 treatments were greater upon resumption of feeding ad libitum. Feed removal for a total of 2 or 4 d did not decrease final body weight, feed consumption, or carcass weight; however, removal for a total of 6 d decreased these variables. Cumulative feed conversion, BW, uniformity, mortality, carcass yield, carcass weight, abdominal fat pad, and feed costs per pound of body and carcass weights were not affected by feed removal. These results indicate subjecting broilers to 4 d of feed removal significantly reduced early growth without compromising final weight or meat recovery.

Effect of level of inclusion and method of presentation of a single distillery by-product on the processes of ingestion of concentrate feeds by horses

The eating behaviour of horses offered wheat distiller grains at varying levels in the concentrate was examined in two experiments. The objective of the study was to evaluate the effect of rate of inclusion and presentation (dry vs. soaked) of wheat distiller’s grains, and the responses in behaviour and processes of intake. In both experiments, the rates of inclusion were 1.00:0, 0.75:0.25, 0.50:0.50, 0.25:0.75 and 0:1.00 for wheat distiller’s grains/concentrate, respectively. The various mixtures of concentrate were offered to 10 horses according to two 5×5 Latin squares for 10 min and the rate of eating and processes of ingestion were assessed. When offered at a rate of 0.75 in the dry matter and not soaked, there was a significant reduction ( P<0.01) in the rate of ingestion of DM and chews per kg DM ( P<0.01). However, the rate of ingestion of soaked mixed concentrate declined rapidly ( P<0.01) when the rate of inclusion was greater than 0.5 of the dry matter. The behavioural responses of the animals were commensurate to the observations of rate of eating in the case of non soaked concentrate. When 0.75 of the concentrate DM was replaced with wheat distiller’s grains, a significant increase ( P<0.05) in the incidence of shorter than expected feeding bouts was observed. However if feeding was terminated, reversion of feeding occurred with a mean frequency of 0.767. The rate of cessation of feeding was also increased significantly when 0.75 or all of the concentrate DM was replaced with the distillery by-product. If the concentrate was soaked before offering, there was an increase ( P<0.05) in the number of feeding bouts when 0.25 of the concentrate was replaced with wheat distiller’s grains. However the processes of ingestion were not affected until 0.5 of the concentrate DM was replaced. Cessation of feeding was affected significantly by the previous behaviour ( P<0.001) especially when the animal interacts with the environment and resumption of feeding was reduced significantly ( P<0.01) as the rate of inclusion of wheat distiller’s grains increased. Wheat distiller’s grains can be used as a substitute to other energy and protein feeding-stuffs in the ration of the horse. However the inclusion rate depends on the method of presentation of the feed to the animal. Soaking of the concentrate prior to feeding allowed a reduced level of distillery by-product to be incorporated into the ration. Least cost formulation of concentrates for horses should therefore consider the nutritive composition of the feeding stuff, the potential of the novel feeding-stuff to disrupt behaviour during feeding and the cost of the formulation.

Feeding resumption, morphological changes and mortality during starvation in Japanese flounder larvae

Japanese flounder Paralichthys olivaceus larvae established first feeding 3 days after hatching (DAH) at c. 17° C. Non‐fed fish reached irreversible starvation at age 5 DAH. Non‐fed fish showed similar feeding rate and feeding intensity as the fed fish when they were provided with prey before 5 DAH, after which the starved larvae did not feed even when prey became available. None of the six morphological measurements examined (total length, body height, eye height, head height, gut height and myotome height) showed significant differences between the non‐fed and fed larvae until 5 DAH. Normal development continued only in the fed group, and the non‐fed larvae showed reverse growth or body collapse after 5 DAH. Owing to the shrinkage and collapse at the top of head due to starvation, head height could be a sensitive indicator of starvation in Japanese flounder larvae. In the fed treatments, high mortality occurred from first feeding (3 DAH) to irreversible starvation (5 DAH), accounting for about two‐thirds to three‐quarters of the overall mortality (46–52%) throughout the experiments. This mortality was not prey density or larval density dependent. Mortality during the same period in the non‐fed larvae accounted for about a third of the overall mortality (100%).

Feeding resumption, morphological changes and mortality during starvation in Japanese flounder larvae

Feeding resumption, morphological changes and mortality during starvation in Japanese flounder larvae

Changes in the population of immunoreactive S-100-positive folliculo-stellate cells in hens during induced molting

The goal of this study was to determine whether the population of folliculo-stellate (FS) cells in the hen's pituitary change during induced molting. White Leghorn laying hens were subjected to induced molting by feed withdrawal; feeding was resumed on the fourth day after egg laying ceased. The anterior pituitaries were collected from hens at pretreatment, at 3 and 5 d after feed withdrawal and at 3 d after cessation of egg laying, 10 d after cessation of egg laying (6 d after resumption of feeding), on the day of and 1 wk after resumption of egg laying (RL and 1WRL, respectively). Pituitaries were processed to detect FS cells by immunocytochemistry for the S-100 protein. Sections were then examined under a light microscope with an image analysis computer system. S-100 immunoreactive cells were found in the cephalic and caudal lobes of the anterior pituitary in all groups of hens. The majority of S-100 immunoreactive cells formed clusters of cells that faced into the follicle and surrounded the glandular cells with long cytoplasmic processes. The S-100 immunoreactive area in the cephalic lobe was significantly increased in the RL group (P < 0.05), but decreased thereafter in 1WRL group. The S-100-positive cell area in the caudal lobe did not show significant changes during induced molting. These results suggest that FS cell population is likely to increase at the final stage of induced molting and may be involved in control of pituitary functions for the resumption of ovulation.

Cell Proliferation and Apoptosis in the Anterior Pituitary of Chicken during Inhibition and Resumption of Laying

The goal of this study was to determine whether tissue rejuvenation of the anterior pituitary with cell proliferation and apoptosis occurs during inhibition and resumption of egg-laying. White Leghorn laying hens were subjected to inhibition of laying by feed withdrawal. Feeding was resumed on the fourth day of egg-laying cessation. All birds were injected ip with bromodeoxyuridine (BrdU) 1 h before tissue collection. The anterior pituitary glands were collected from hens of the following groups: pretreatment (PT), 3 and 5 days after starvation (3DS and 5DS, respectively), 3 days after cessation of laying (3DC), 10 days after cessation of laying (10DC, 6 days after resumption of feeding), and the day of and 1 week after resumption of laying (RL and 1WRL, respectively). They were processed for the detection of proliferating cells and apoptotic cells by BrdU immunostaining and terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick-end-labeling (TUNEL). Immunostaining for the anterior pituitary hormones was also conducted. In the cephalic lobe the BrdU-positive cells showed a higher frequency in RL than in PT, 3DC, and 1WRL. BrdU-positive cell frequency in the caudal lobe was greater in RL than in PT. TUNEL-positive cells in both cephalic and caudal lobes were increased markedly in the RL group. Their frequency in the cephalic lobe was greater in RL than in PT, and that in the caudal lobe of RL was higher than in any other group of birds. The areas of FSH-like cells in 10DC and RL were greater than those in PT to 3DC, and those of LH-like cells in RL were greater than those of 3DS to 3DC. PRL-like cells were decreased until 3DC and then gradually increased until 1WRL. GH-, TSH-, and ACTH-like cell areas showed tendencies to increase until 3DC, with decreasing thereafter. The sizes of FSH-like cells in 10DC to 1WRL and LH-like cells in RL were larger than those around cessation of laying. These results suggest that during inhibition and resumption of laying cell proliferation and apoptosis occur in the anterior pituitary tissue, which may cause a rejuvenation of tissue to improve the function of this organ.

Behaviour of domestic ducks exposed to mobile predator stimuli. 1. Flock responses

1. Small flocks of ducks ( Anas platyrhynchos domesticus ) were exposed to two stimuli, a small mobile vehicle and a walking human, to investigate their flight responses. 2. Experiment 1. Flocks were herded around an annular arena by each stimulus at 0.5 ms-1 and the flight distance between the stimulus and the centre of the flock, and individual positions within the flock were recorded every 10 s. Flocks maintained a significantly longer distance from the human (6.0 m) than the vehicle (5.1 m) and usually did not maintain visual contact with either stimulus. Significant consistency in individual positions within the flock was found within and between trials. 3. Experiment 2. Flocks were exposed to each stimulus which approached them as they were feeding in a circular arena. The latencies for cessation and resumption of feeding were recorded and the paths followed by the flocks described. Ducks showed a significantly shorter latency to cease feeding in response to the human (4.9 s) compared with the vehicle (6.9 s). 4. Domestic ducks apparently perceive an approaching human as a greater threat than a small vehicle. The findings are discussed in relation to the development of herding robots.

Feeding demand conditions and plasma cortisol in socially-housed squirrel monkey mother-infant dyads.

Previous studies have demonstrated that experimentally altering the accessibility and availability of food can have profound impact on behavior and adrenocortical activity in nonhuman primate species. In this study, groups of mother-infant squirrel monkey dyads were housed in either high demand (HFD: 120% normal daily food intake provided), low demand (LFD: 600% normal daily food intake provided) or variable demand (VFD: alternating two-week blocks of low demand and high demand) conditions for 12 weeks. During the 12-week experimental foraging phase, animals in the HFD group exhibited prolonged and consistent cortisol elevations. The cortisol levels in the VFD group reflected the ambient demand condition, with higher levels exhibited during the high demand phases of the study, and lower values when the low demand condition was in effect. Overall, mothers were more affected by the experimental manipulation than were infants. The experimental condition did not affect the infants' response to a 24-h separation from their mothers. A suppression of cortisol levels, particularly in the HFD group, was observed upon resumption of ad-libitum feeding.

MORTALITY, FEEDING INHIBITION, AND RECOVERY OF SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) LARVAE FOLLOWING AERIAL APPLICATION OF A HIGH-POTENCY FORMULATION OF BACILLUS THURINGIENSIS SUBSP. KURSTAKI

AbstractA larval population of spruce budworm, Choristoneura fumiferana (Clemens), was monitored for 5 d following aerial application of a commercial formulation of Bacillus thuringiensis Berliner subsp. kurstaki to investigate dose acquisition and expression (larval mortality, recovery, feeding, and growth) in relation to spray deposition and persistence of spray deposits. The main objective was to test if previous laboratory observations on how B. thuringiensis affects feeding and dose ingestion by spruce budworm larvae hold true under field conditions. About 40% of the treated population ingested a lethal dose within 1 d after spray application. Lethally dosed larvae died without further feeding upon transfer from treated foliage to (untreated) artificial diet. Resumption of feeding by larvae that survived the treatment was delayed relative to larvae from the control population during 3 d following spray application; during that time, normal feeding activity and larval weight gain were suppressed. Inhibited feeding by survivors appeared to prevent further dose uptake because the proportion of lethally dosed larvae in daily collections did not increase despite significant residual spray deposits in budworm feeding sites. Restoration of "normal" recovery times by the fourth day coincided with a 65–85% reduction in persistence of the pathogen on the foliage and did not result in further lethal dose acquisition, as treatment-induced mortality dropped to about 20% on the 4th and 5th days. The observations are consistent with previous laboratory observations of how B. thuringiensis affects larval feeding and with the hypothesis that feeding inhibition may be a limiting factor in the acquisition of a lethal dose.

Patterns of respiration in Locusta migratoria nymphs when feeding

SummaryFlow‐through respirometry was used to investigate patterns of respiration of fifth‐instar Locusta migratoria L. nymphs fed a chemically defined, synthetic food. Each animal was recorded for up to 2.7 h, during which they had access to food and water ad libitum, and at least one meal was taken. The start of feeding was coincident with a sudden and rapid rise in respiration. Both carbon dioxide (CO2) production and oxygen (O2) consumption rose, the traces for the two gasses showing a high degree of alignment. The end of a meal correlated with a sudden and rapid decrease in respiratory rate towards resting levels. When feeding was interrupted by an intra‐meal pause, respiratory rate tended to drop marginally and then stabilize, before rising rapidly upon the resumption of feeding within the meal. Maximal rates of respiration during feeding represented a 3–4‐fold increase over those at rest. Walking and climbing within the chamber were not associated with any noticeable change in respiratory rate above baseline. When locusts were quiescent between feeding episodes, respiration was steady and continuous, rather than discontinuous. Possible causes for large changes in respiration during feeding are discussed.

Effects of developmental age, ambient temperature, and dietary alterations on delta(12) desaturase activity in the house cricket, Acheta domesticus.

Double bond formation in polyunsaturated fatty acids (PUFA) is mediated by desaturase enzymes. Certain insect species have been found to possess a Delta(12) desaturase, previously thought to occur exclusively in plants. We have begun to characterize this enzyme to determine its relatedness to those found in plants and animals. Desaturase activity can be altered significantly by a number of environmental factors in protozoa, cyanobacteria, plants, fish, and rats. We present evidence here that Delta(12) desaturase activity in Acheta domesticus is affected by developmental stage, starvation, dietary alterations, and fluctuations in ambient temperature. Highest activity is observed during the middle of the penultimate instar and 3 to 6 days after adult emergence. Starvation markedly decreases Delta(12) activity, whereas resumption of feeding on fat-free or low fat diets increases activity.

Delayed postoperative gastric emptying following intrathecal morphine and intrathecal bupivacaine

A decrease in the rate of gastric emptying can delay resumption of enteral feeding, alter bioavailability of orally administered drugs, and result in larger residual gastric volumes, increasing the risk of nausea and vomiting. We compared the effects of 1) intrathecal bupivacaine (17.5 mg) and 2) the combination of intrathecal morphine (0.6 mg) and intrathecal bupivacaine (17.5 mg) on the rate of gastric emptying in patients undergoing elective hip arthroplasty. Twenty four fasting ASA 1-3 patients were randomly assigned, in a double blind manner, to receive intrathecal hyperbaric bupivacaine (17.5 mg), either alone (group 1), or followed by intrathecal morphine (0.6 mg) (group 2). Gastric emptying was measured (using an acetaminophen absorption technique), twice in each patient; preoperatively, and approximately one hour postoperatively. Gastric emptying parameters are: AUC (area under the plasma acetaminophen concentration time curve), maximum plasma acetaminophen concentration (Cmax), and time to Cmax (tCmax), analyzed using paired Student's t tests. Gastric emptying rates were reduced in both group 1 (AUC = 14.98 (3.8) and 11.05 (4.6) pre- and postoperatively, respectively) and group 2 (AUC = 13.93 (3.59) and 6.4 (3.42) pre- and postoperatively, respectively); the magnitude of the reduction was greater in group 2 [AUC (P = 0.04), Cmax (P = 0.05), tCmax (P = 0.13)]. The combination of intrathecal morphine (0.6 mg) and intrathecal bupivacaine (17.5 mg) delays gastric emptying postoperatively.

Elemental (C, N and P) analysis of metamorphosing bonefish ( Albula sp.) leptocephali: relationship to catabolism of endogenous organic compounds, tissue remodeling, and feeding ecology

Whole-body carbon (C), nitrogen (N) and phosphorus (P) content, and stable-isotope composition (13C:12C and 15N:14N), were followed during metamorphosis of bonefish (Albula sp.) larvae (leptocephali). Metamorphosing larvae depend entirely on endogenous carbon compounds (some of which contain N and P) as an energy source. Two fundamental questions are (1) Do the demands of extensive tissue remodeling during metamorphosis require the efficient retention of N and P during the catabolism of carbon compounds? (2) What effect does the lack of feeding have on stable-isotope composition? Our results showed that both C and N decreased by ∼35 to 40%, reflecting the utilization of neutral lipid (triacylglycerols) and N-containing compounds (phosphatidylethanolamine and keratan sulfate glycosaminoglycan) as energy sources, and indicating that larvae have little or no capacity to retain N. Evidence suggested that collagen breakdown, measured as a loss of hydroxyproline content, also contributed to N loss. Stable-isotope ratios, expressed as 13C and 15N, showed no statistically significant differences in early and advanced metamorphosing larvae. In contrast to C and N, phosphorus was conserved during metamorphosis and most probably is utilized in the increased bone mineralization occurring in advanced larvae. We show, however, that advanced larvae are P-limited and that normal ossification is dependent upon a supply of exogenous P obtained after the resumption of feeding. The N:P ratio of 12.3 in early larvae decreased to 8.1 in advanced larvae owing to the conservation of P as N was lost. The mean 15N value in early metamorphic larvae (11.6‰) is consistent with results from other studies, and provides further support for the view that premetamorphic leptocephali feed at a very low trophic level.

Stenting for caustic strictures: Esophageal replacement replaced

Methods: From 1983 to 1996, 31 children with caustic esophageal strictures were seen at Bambino Gesù Children's Hospital; they were all treated conservatively except for two cases complicated by tracheoesophageal fistula. The remaining 29 patients were divided into three groups depending on the treatment, which was modified over the years. Group A (1983 to 1987) consisted of seven patients treated by periodic dilatations; group B (1988 to 1992) consisted of 10 children treated by 40 days of esophageal stenting plus dexamethasone, 0.5 mg/kg/d plus ranitidine plus no oral feeding for 7 to 10 days; group C (1993 to 1996) consisted of 12 cases treated by 40 days of esophageal stenting plus dexamethasone, 1 mg/kg/d plus omeprazole plus early oral feeding resumption. Results: No differences were observed between the three groups of patients with regard to the mean age and to the ingested substance, whereas a significant difference ( P = .007) was observed in the mean length of the stricture between group A and C (3.4 ± 1.3 and 5.6 ± 1.6 cm, respectively). In all but one of the patients (96.5%) complete healing of the stenosis was achieved by conservative treatment, with definitive relief of dysphagia. One patient in group C did not improve after a repeated stenting procedure and was surgically treated. However, in group A, resolution of the stricture was obtained after an average of 19.9 ± 14.8 dilatations in a mean period of 25.3 ± 17.2 months. In group B, a mean of 12 ± 11.3 dilatations were required in a mean period of treatment of 14.1 ± 10.6 months. In patients in group C, a mean of 3.5 ± 3.2 dilatations were necessary in a mean of 5.8 ± 4.8 months. A statistically significant difference was observed both with regard to the number of dilatations and to the duration of treatment, between group A and group C ( P = .002) and group B and C ( P = .03). Conclusion: Esophageal replacement should be considered only in cases complicated by tracheoesophageal fistula or in the rare patients who do not respond to repeated esophageal stenting.

Seasonal variation in trypsin activity in juvenile Atlantic salmon upper and lower modal groups.

Juvenile salmon in their first year of growth showed a bimodal distribution of body lengths by December. For experimental purposes samples of fish from the upper 2% of body lengths were taken as representing the upper modal group (UMG), whilst fish from the bottom 5% of body lengths were taken to represent the lower modal group (LMG). The population of fish from which the samples were taken were fed ad libitum from December to July. During the winter months to March, neither group increased in weight. Growth resumed between March and July. The LMG fish had a very low food intake, as indicated by the relative weight of digesta in the stomach, in the winter months. However, following resumption of feeding, the relative weight of stomach digesta of the LMG fish exceeded that of the UMG fish between May and July. The activity of trypsin in the intestinal digesta followed a similar pattern, the LMG fish showing a higher trypsin activity in the spring months. Starvation of UMG fish for 5 days in winter resulted in accumulation of trypsin in the pancreatic tissues, whilst injection of the trypsin releasing hormone cholecystokinin (CCK) into starving UMG fish resulted in reduction of trypsin in the secretory tissues. CCK also caused reduction of trypsin in the pancreatic tissues of LMG fish, suggesting that the pancreas of this group is potentially fully functional during the winter period. Ultrastructure studies of the pancreatic acinar cells showed evidence for lower secretory activity in the LMG fish, as indicated by smaller numbers of zymogen granules, less well developed Golgi systems and a smaller number of active secreting cells. It appears that trypsin secretion by the pancreas in LMG fish is at a low level during the winter, in response to the reduced amounts of food passing through the gut, which is ultimately controlled by changes in food intake, lowered metabolic level and lowered appetite levels.