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Biomedical subjects

A Lapillonne

Publications and source records attributed to A Lapillonne.

At least 19 recordsLinked to original sources

Polyunsaturated fatty acids and infant growth.

Because of the rapid rate of growth during infancy, and the potentially deleterious effect of differences in the availability of dietary essential nutrients, growth is an important outcome variable in any study assessing a diet designed for infants. Nearly 10 yr after the first demonstration of reduced growth in preterm infants fed a fish oil-enriched formula, there is very little additional information to confirm or refute the finding that long-chain n-3 polyunsaturated fatty acid (LC-PUFA) intake can modulate growth in infants. To evaluate the issue of a possible relationship between PUFA intake and growth of infants, we reviewed a total of 32 randomized studies, 13 in preterm infants and 19 in term infants. From the data published to date, it seems clear that long-chain n-3 fatty acids can reduce growth achievement in preterm and term infants under some experimental conditions. However, the effect of n-3 PUFA supplementation on the growth of preterm and term infants appears to be minimal and of questionable clinical and/or physiologic relevance. Nonetheless, n-3 fatty acids have an effect on gene transcription, at least in some species, and this finding may provide important clues to the mechanism by which n-3 and n-6 fatty acids regulate growth.

Fatty Acids, Omega-3↗

Nutritional efficacy of preterm formula with a partially hydrolyzed protein source: a randomized pilot study.

BACKGROUND: Decreased nitrogen levels, calcium intestinal absorption rates, and plasma amino acid imbalances were reported for preterm infants who were fed partially hydrolyzed preterm formulas. In this pilot study, we evaluated a new formula with modified nitrogen and calcium sources. METHODS: During their second week of life, 16 preterm infants were randomly assigned to one of two groups: 9 were fed the new partially hydrolyzed formula and 7 were fed a conventional formula. Nutrient balance was performed at the end of the first month of life. Amino acid concentrations and anthropometric parameters were measured at theoretical term. RESULTS: Birth weight and gestational age (mean +/- SD) were similar in the two groups (28.9 +/- 7.0 weeks and 1183 +/- 242 g vs. 27.7 +/- 1.0 weeks and 1139 +/- 162 g). Median nitrogen absorption rates (85% vs. 89%; P = 0.03) and biological values (59% vs. 69%; P = 0.13) were lower for infants who were fed the new formula than for those fed the conventional formula. After correction for difference in nitrogen intake, there was no significant difference in nitrogen retained between the two groups (P = 0.11). Plasma amino acid concentrations were also similar in the two groups. Median calcium absorption tended to be higher in the new-formula group than in the conventional-formula group (54% vs. 45%, P = 0.19). At theoretical term, infants fed the conventional formula were heavier than infants fed the new formula (3559 +/- 362 g vs. 3193 +/- 384 g, P = 0.04). CONCLUSIONS: Because nitrogen content is 10% higher in hydrolyzed-protein formula than in entire-protein formula, appropriate nitrogen retention, plasma amino acid profile, and mineral use can be achieved with the new partially hydrolyzed formula. Further studies with larger groups are needed to evaluate the effect on growth.

Amino Acids↗

Vitamin D deficiency in Iranian mothers and their neonates: a pilot study.

UNLABELLED: We conducted a pilot study to assess the prevalence of hypovitaminosis D among Iranian women and their newborns. Blood samples were taken from 50 mothers (age 16-40 yr) and their neonates at term delivery in the largest Tehran hospital. The results showed that 80% of the women had 25-hydroxyvitamin D (25-OHD) concentrations of less than 25 nmol/l. Mean maternal plasma calcium and phosphatase alkaline concentrations were in the normal range. The mean maternal serum immunoreactive parathyroid hormone concentration of women with hypovitaminosis D (i.e., 25-OHD levels <25 nmol/l) was above normal range and significantly different from that of women without hypovitaminosis D. CONCLUSION: The mean cord serum 25-OHD concentration was very low (4.94+/-9.4 nmol/l) and that of infants of mother with hypovitaminosis D were almost undetectable (1.2+/-1.2 nmol/l).

Adolescent↗

New insights into the postnatal growth of infants born 'idiopathic' small for gestational age.

Infants born small for gestational age (SGA) are defined as those with a birth weight and/or birth length below two standard deviations for gestational age. Postnatal catch-up growth is absent in 8-12% of children born SGA and these children achieve adult heights far below their target height. The objectives of our retrospective study were to confirm the prevalence of catch-up growth and to refine the kinetics of the catch-up process. The 'Lyon series' of patients consisted of 179 children with 'idiopathic' SGA, of whom 8% did not achieve catch-up growth (i.e. their height remained below -2 SD throughout the study). The number of days that the mother was hospitalized before delivery was found to be significantly correlated with lack of catch-up growth. Maternal hypertension, term delivery and postnatal parenteral nutrition were also associated with lack of catch-up growth, but the relationship was not significant. In addition, an oscillatory growth velocity pattern was observed in boys and girls born SGA, with alternating periods of growth acceleration and deceleration. This suggests that catch-up growth is regulated in a sophisticated way by the hypothetical 'Somatostat', although further confirmation of this process is needed.

Female↗

Absence of perilipin results in leanness and reverses obesity in Lepr(db/db) mice.

Obesity is a disorder of energy balance. Hormone-sensitive lipase (HSL) mediates the hydrolysis of triacylglycerol, the major form of stored energy in the body. Perilipin (encoded by the gene Plin), an adipocyte protein, has been postulated to modulate HSL activity. We show here that targeted disruption of Plin results in healthy mice that have constitutively activated fat-cell HSL. Plin -/- mice consume more food than control mice, but have normal body weight. They are much leaner and more muscular than controls, have 62% smaller white adipocytes, show elevated basal lipolysis that is resistant to beta-adrenergic agonist stimulation, and are cold-sensitive except when fed. They are also resistant to diet-induced obesity. Breeding the Plin -/- alleles into Leprdb/db mice reverses the obesity by ncreasing the metabolic rate of the mice. Our results demonstrate a role for perilipin in reining in basal HSL activity and regulating lipolysis and energy balance; thus, agents that inactivate perilipin may prove useful as anti-obesity medications.

Adipose Tissue↗

Functional cystic fibrosis transmembrane conductance regulator tagged with an epitope of the vesicular stomatis virus glycoprotein can be addressed to the apical domain of polarized cells.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a phosphorylation-activated chloride channel apically localized in epithelial cells. In cystic fibrosis patients, the gene encoding this N-linked glycoprotein is mutated. About 70% of CF patients express a mutated form of CFTR, deleted at the phenylalanine residue at position 508 (deltaF508). CFTR-deltaF508 fails to exit the endoplasmic reticulum; it remains incompletely glycosylated and is rapidly degraded. To optimize CFTR detection for membrane localization studies and biochemical studies, we tagged wild-type and deltaF508 CFTR with the VSV-G epitope at their carboxy-terminal ends. We have generated pig kidney epithelial cell clones (LLCPK1) expressing VSV-G-tagged human wild-type and deltaF508-CFTR. In CFTR-expressing cells, the transfected protein is maturated and transported to the apical membrane where it is concentrated. The cells exhibit a strong anion channel activity after stimulation by cAMP, as demonstrated by a halide sensitive fluorescent dye assay (6-methoxy-N-ethylquinominium, SPQ), and whole-cell patch-clamp approach. This activity of CFTR-VSV-G is indistinguishable from the wild-type CFTR. In contrast, in cells expressing tagged deltaF508-CFTR or in non-transfected cells, no anion channel activity could be detected after stimulation by cAMP. In deltaF508-CFTR-VSV-G-expressing cells, the mutated CFTR remained in the incompletely glycosylated form and was localized in the endoplasmic reticulum. These cell lines reproduce the cellular fate of wild-type and mutated CFTR-deltaF508. To our knowledge, they are the first differentiated epithelial cell lines stably expressing tagged CFTR and CFTR-deltaF508 in which cellular processing and functional activity of these two proteins are reproduced. Thus the addition of the VSV-G epitope does not impair the localization and function of CFTR, and these cell lines can be used to examine CFTR function in vitro.

Cell Line↗

Perinatal metabolism of vitamin D.

During pregnancy, maternal serum concentrations of 25-hydroxyvitamin D, the circulating form of vitamin D, correlate with dietary vitamin D intake. Maternal serum concentrations of 1,25-dihydroxyvitamin D, the hormonal circulating and active form of vitamin D, are elevated during pregnancy; 1,25-dihydroxyvitamin D is synthesized mainly by the decidual cells of the placenta and allows for increased calcium absorption. The fetus is entirely dependent on the mother for its supply of 25-hydroxyvitamin D, which is believed to cross the placenta. Hypocalcemia and increased parathyroid hormone secretion induce synthesis of 1,25-dihydroxyvitamin D after birth in both full-term and preterm neonates. Nevertheless, serum concentrations of 25-hydroxyvitamin D are a rate-limiting factor in the synthesis of 1,25-dihydroxyvitamin D. In vitamin D-replete infants, circulating 1,25-dihydroxyvitamin D concentrations are higher than those observed in older infants. In countries where dairy products are not routinely supplemented with vitamin D, maternal vitamin D supplementation during pregnancy is necessary. However, there is no indication for the use of pharmacologic doses of vitamin D or its metabolites in the perinatal period.

Dietary Supplements↗

Effects of liver transplantation on long-chain polyunsaturated fatty acid status in infants with biliary atresia.

BACKGROUND: The long-chain polyunsaturated fatty acid (LC-PUFA) status of infants with untreated biliary atresia (BA) is known to be poor and is correlated to the severity of the liver disease. Liver transplantation (LT) markedly increases survival of patients with BA but the extent to which this reverses poor LC-PUFA status is not known. METHODS: To explore this question, the erythrocyte (red blood cell, RBC) phospholipid content of eight infants with BA who underwent LT was determined 2 months after an initial portoenterostomy, immediately before LT, and 6 and 12 months after LT. Before LT, all infants were fed a protein hydrolysate formula containing medium-chain triglycerides and essential fatty acids. Afterward, they were fed a normal diet for age. The RBC phospholipid content at each time point was compared with that of 28 age-matched control infants. RESULTS: Just before LT, median RBC phospholipid content of C20:4n-6, C20:5n-3, and C22:6n-3 was 25%, 48%, and 30% lower, respectively, than that observed in age-matched control infants. After LT, the RBC phospholipid content of most fatty acids reached normal values by 6 months. However, that of C20:4n-6 and C22:6n-3 contents remained 5% and 15% lower, respectively, than in normal control infants. Twelve months after LT, C20:4n-6 content remained lower than in normal children, but that of C22:6n-3 did not differ. The ratio of C20:3n-6/C20:4n-6, a reflection of delta-5 desaturase activity, was abnormal compared with normal children before LT (0.17 vs. 0.10, P < 0.009) but normalized by 6 months after LT (0.11 vs. 0.10, not significant). CONCLUSIONS: These data show that the abnormal LC-PUFA status of children with BA improves after LT but is not entirely reversed within a year after surgery. They suggest that the abnormal status before LT may be secondary, in part, to low delta-5 desaturase activity. The extent to which a different pre- and/or post-LT diet can prevent PUFA deficiency and/or hasten recovery of PUFA status remains to be determined.

Biliary Atresia↗

The use of low-EPA fish oil for long-chain polyunsaturated fatty acid supplementation of preterm infants.

Because docosahexaenoic acid (DHA) may be an essential nutrient for the visual and early cognitive development of preterm infants, DHA enrichment of preterm formulas has been recommended. This randomized trial was designed to study the n-6 and n-3 fatty acid status of healthy preterm infants fed a formula enriched with a low eicosapentaenoic-fish oil until 4 mo corrected age compared with that of infants fed a standard formula. A reference group of breast-fed infants was studied concurrently. The fatty acid content of red blood cell (RBC) phospholipid was assessed at enrollment, hospital discharge, expected term, and 3 and 6 mo postterm. The DHA content of RBC phospholipid was higher in infants fed the enriched versus the standard formula at hospital discharge, expected term, and 3 and 6 mo postterm. However, compared with infants fed the standard formula, infants fed the enriched formula had also higher RBC phospholipid eicosapentaenoic content (0.69 +/- 0.15% versus 0.25 +/- 0.12%, p < 0.001), and lower RBC phospholipid arachidonic acid content (15.1 +/- 0.93% versus 18.8 +/- 0.89%; p < 0.001). We conclude that supplementing preterm infants with low-eicosapentaenoic fish oil is effective in improving DHA status, but results in worsening of n-6 fatty acid status. We speculate that preterm infants may require a dietary supply of arachidonic acid as well as DHA if the same fatty acid status as that of breast-fed infants is to be achieved.

Arachidonic Acid↗

In vivo, villin is required for Ca(2+)-dependent F-actin disruption in intestinal brush borders.

Villin is an actin-binding protein localized in intestinal and kidney brush borders. In vitro, villin has been demonstrated to bundle and sever F-actin in a Ca(2+)-dependent manner. We generated knockout mice to study the role of villin in vivo. In villin-null mice, no noticeable changes were observed in the ultrastructure of the microvilli or in the localization and expression of the actin-binding and membrane proteins of the intestine. Interestingly, the response to elevated intracellular Ca(2+) differed significantly between mutant and normal mice. In wild-type animals, isolated brush borders were disrupted by the addition of Ca(2+), whereas Ca(2+) had no effect in villin-null isolates. Moreover, increase in intracellular Ca(2+) by serosal carbachol or mucosal Ca(2+) ionophore A23187 application abolished the F-actin labeling only in the brush border of wild-type animals. This F-actin disruption was also observed in physiological fasting/refeeding experiments. Oral administration of dextran sulfate sodium, an agent that causes colonic epithelial injury, induced large mucosal lesions resulting in a higher death probability in mice lacking villin, 36 +/- 9.6%, compared with wild-type mice, 70 +/- 8.8%, at day 13. These results suggest that in vivo, villin is not necessary for the bundling of F-actin microfilaments, whereas it is necessary for the reorganization elicited by various signals. We postulate that this property might be involved in cellular plasticity related to cell injury.

Actin Cytoskeleton↗

Cystic adenomatoid malformation of the lung: neonatal management of 21 cases.

Currently, congenital cystic adenomatoid malformation of the lung (CCAM) is often diagnosed antenatally by ultrasound, allowing prompt and appropriate medical and surgical management after birth. The authors report 21 cases of CCAM admitted from 1988 to 1997 to a neonatal intensive care unit and treated by high-frequency oscillation (HFO) and early surgery. Six infants developed respiratory distress, of whom 4 required ventilation by HFO. HFO was also the mode of ventilation used in all cases except 1 during the perioperative period. There was no death from respiratory failure. The authors emphasize the usefulness of antenatal diagnosis, the efficiency of HFO in cases with severe respiratory failure, and well-tolerated early surgery.

Combined Modality Therapy↗

Immunodetection of the microvillous cytoskeleton molecules villin and ezrin in the parasitophorous vacuole wall of Cryptosporidium parvum (Protozoa: Apicomplexa).

Microvilli - actin - villin - ezrin - Cryptosporidium parvum The sporozoites and merozoites of the Apicomplexan protozoan Cryptosporidium parvum (C. parvum) invade the apical side of enterocytes and induce the formation of a parasitophorous vacuole which stays in the brush border area and disturbs the distribution of microvilli. The vacuole is separated from the apical cytoplasm of the cell by an electron-dense layer of undetermined composition. In order to characterize the enterocyte cytoskeleton changes that occur during C. parvum invasion and development, we used both confocal immunofluorescence and immunoelectron microscopy to examine at the C.parvum-enterocyte interface the distribution of three components of the microvillous skeleton, actin, villin and ezrin. In infected cells, rhodamine-phalloidin and anti-villin and anti-ezrin antibodies recognized ring-like structures surrounding the developing parasites. By immunoelectron microscopy, both villin and ezrin were detected in the parasitophorous vacuole wall surrounding the luminal and lateral sides of the intracellular parasite. In contrast, anti-beta and anti-gamma actin antibodies showed no significant labelling of the vacuolar wall. These observations indicate that the parasitophorous vacuole wall contains at least two microvillus-derived components, villin and ezrin, as well as a low amount of F-actin. These data suggest that C.parvum infection induces a rearrangement of cytoskeleton molecules at the apical pole of the host cell that are used to build the parasitophorous vacuole.

Actins↗

[Precocious maturation of auditory evoked potentials in prematures: influence of gestational age and sex].

In humans, the onset of the auditory function occurs at the beginning of the third trimester of pregnancy. Brainstem auditory evoked potentials (BAEPs) can be recorded in preterm neonates as early as 25-26 weeks of gestational age. The latency of BAEP waves show a significant decrease according to increasing age to achieve adult values at the end of the first month after birth for wave I and near 3 to 5 years old for waves III and V. Auditory evoked responses are influenced by gender, notably with significantly higher wave latencies in males than in females. These gender differences in auditory function appear early in humans, some being observed as soon as 34 weeks of gestational age.

Adult↗

Dual-energy X-ray absorptiometry in small subjects: influence of dual-energy X-ray equipment on assessment of mineralization and body composition in newborn piglets.

There is a growing body of literature that describes the use of dual-energy x-ray absorptiometry (DXA) for bone mineral content (BMC) and fat mass (FM) assessment in neonates, but the reproducibility and accuracy of the method are still controversial. Two different software programs have been developed for use on Hologic densitometers: the Pediatric Whole Body (PWB) and the Infant Whole Body (IWB) programs. They differ in scan time, radiation exposure, and in the algorithm used to assess BMC. We evaluated the reproducibility and accuracy of PWB and IWB in newborn piglets. Reproducibility of body mass (BM), FM, and BMC measurements from PWB and IWB were similar. BM agreed well with scale weight with both software programs; IWB was within +/- 0.5% and PWB was within +/- 0.3% of scale weight. FM was highly correlated with carcass fat (PWB: r = 0.962; IWB: r = 0.980). Errors in the DXA estimation of fat were similar with PWB and IWB. With both software programs, BMC was highly correlated with carcass calcium (PWB: r = 0.925, IWB: r = 0.987), but errors in the DXA estimation of calcium were about twice as high with PWB (+/- 16.9%) than with IWB (+/-9.2%). In four piglets, the addition of a layer of porcine lard was associated with an increase in BMC; this effect was more pronounced with PWB (+ 156%) than with IWB (+ 15%). The IWB software provided BMC measurements that were more precise, accurate, and stable in the presence of added fat than the measurements obtained with PWB, indicating that IWB is superior to PWB for in vivo determination of BMC and body composition.

Absorptiometry, Photon↗