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Mosoni, L., T. Malmezat, M. C. Valluy, M. L. Houlier, D. Attaix, and P. Patureau Mirand. Lower recovery of muscle protein lost during starvation in old rats despite a stimulation of protein synthesis. Am. J. Physiol. 277 (Endocrinol. Metab. 40): E608-E616, 1999.--Sarcopenia could result from the inability of an older individual to recover muscle lost during catabolic periods. To test this hypothesis, we compared the capacity of 5-day-refed 12- and 24-mo-old rats to recover muscle mass lost after 10 days without food. We measured gastrocnemius and liver protein synthesis with the flooding-dose method and also measured nitrogen balance, 3-methylhistidine excretion, and the gene expression of components of proteolytic pathways in muscle comparing fed, starved, and refed rats at each age. We show that 24-mo-old rats had an altered capacity to recover muscle proteins. Muscle protein synthesis, inhibited during starvation, returned to control values during refeeding in both age groups. The lower recovery in 24-mo-old rats was related to a lack of inhibition of muscle proteolysis during refeeding. The level of gene expression of components of the proteolytic pathways did not account for the variations in muscle proteolysis at both ages. In conclusion, this study highlights the role of muscle proteolysis in the lower recovery of muscle protein mass lost during catabolic periods. sarcopenia; aging; proteolysis; flooding dose; 3-methylhistidine

This study was undertaken to determine whether a pulse protein feeding pattern was more efficient than a spread pattern to improve protein anabolism in young women as was already shown in elderly women. After a 15-d adaptive period [1.2 g protein/(kg fat-free mass. d)], 16 young women (age 26 +/- 1 y) were given a 14-d diet providing 1.7 g protein/(kg fat-free mass. d), using either a pulse pattern (protein consumed mainly in one meal, n = 8), or a spread pattern (spreading daily protein intake over four meals, n = 8). Nitrogen balance was determined at the end of both the 15-d adaptive and the 14-d experimental periods. Whole-body protein turnover was determined at the end of the 14-d experimental period using [(15)N]glycine as an oral tracer. Nitrogen balance was 17 +/- 5 mg N/(kg fat-free mass. d) during the adaptive period. It was higher during the experimental period, but not significantly different in the women fed the spread or the pulse patterns [59 +/- 12 and 36 +/- 8 mg N/(kg fat-free mass. d) respectively]. No significant effects of the protein feeding pattern were detected on either whole-body protein turnover [5.5 +/- 0.2 vs. 6.1 +/- 0.3 g protein/(kg fat-free mass. d) for spread and pulse pattern, respectively] or whole-body protein synthesis and protein breakdown. Thus, in young women, these protein feeding patterns did not have significantly different effects on protein retention. [ABSTRACT FROM AUTHOR]

Background: Balanced chromosomal rearrangements associated with abnormal phenotype are rare events, but may be challenging for genetic counselling, since molecular characterisation of breakpoints is not performed routinely. We used next-generation sequencing to characterise breakpoints of balanced chromosomal rearrangements at the molecular level in patients with intellectual disability and/or congenital anomalies., Methods: Breakpoints were characterised by a paired-end low depth whole genome sequencing (WGS) strategy and validated by Sanger sequencing. Expression study of disrupted and neighbouring genes was performed by RT-qPCR from blood or lymphoblastoid cell line RNA., Results: Among the 55 patients included (41 reciprocal translocations, 4 inversions, 2 insertions and 8 complex chromosomal rearrangements), we were able to detect 89% of chromosomal rearrangements (49/55). Molecular signatures at the breakpoints suggested that DNA breaks arose randomly and that there was no major influence of repeated elements. Non-homologous end-joining appeared as the main mechanism of repair (55% of rearrangements). A diagnosis could be established in 22/49 patients (44.8%), 15 by gene disruption ( KANSL1 , FOXP1 , SPRED1 , TLK2 , MBD5 , DMD , AUTS2 , MEIS2 , MEF2C , NRXN1 , NFIX , SYNGAP1, GHR, ZMIZ1 ) and 7 by position effect ( DLX5 , MEF2C , BCL11B , SATB2, ZMIZ1 ). In addition, 16 new candidate genes were identified. Systematic gene expression studies further supported these results. We also showed the contribution of topologically associated domain maps to WGS data interpretation., Conclusion: Paired-end WGS is a valid strategy and may be used for structural variation characterisation in a clinical setting., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Kikuchi-Fujimoto disease, also known as histiocytic necrotizing lymphadenitis, is a rare cause of lymphadenopathy in children. This benign disease can mimic lymphoma and misleads doctors. It was first described in Asia, where it occurred especially in young women. Recent publications show that it can also affect teenagers and young adults in Caucasian populations. The pathophysiology remains unknown. Three hypotheses have been raised for this disease: the role of viruses (in particular HHV-8), genetic predisposition (two alleles in HLA class II genes were found more frequently in patients with Kikuchi disease), and an autoimmune cause because of the correlation with lupus erythematosus. Few cases have been reported in Europe so far. In this article, we report three cases of Kikuchi disease observed in less than 2 months in a single hospital in France. All three patients were teenagers who presented with lymphadenopathy, either isolated or combined with fever, weakness, and weight loss. In all of them, the hypermetabolic activity of the lymph node on the PET scanner misled us to suspect lymphoma. The diagnosis of Kikuchi disease was finally made, for all patients, after 2 weeks in the hospital based on lymph node biopsy. Based on this report, we highlight that early biopsy in presence of lymphadenopathy can avoid unnecessary extensive investigations. Moreover, in this rare disease, it is very surprising to come across three cases that are not family-related, in such a short period of time. This strengthens the hypothesis of the possible implication of an environmental factor in the pathophysiology of Kikuchi disease., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Objectives: To evaluate the association between the presence of antiphospholipid (APL) antibodies and the occurrence of autism spectrum disorder (ASD) in childhood., Methods: A prospective, monocentric case-control study from February 2012 to August 2014 comparing the APL antibodies of children with ASD (group 1) and children without ASD (group 2)., Results: Group 1 consisted of 44 children with ASD defined by clinical, genetic, metabolic, and morphological criteria. Group 2 consisted of 26 control children without ASD. One of children with ASD (2.3 %) had persistent anticardiolipin (ACL) antibodies, five of them (11.4 %) had persistent APL antibodies, one of them (2.3 %) had antiannexin V (AAV) antibodies, and two of them (4.5 %) had antiphosphatidylethanolamine (APE) antibodies. Two of the control children (7.7 %) had persistent APL antibodies. None of them had persistent ACL, AAV, or APE antibodies. Comparing group 1 and 2 children, no significant difference was found between the presence and the titers of conventional and non conventional antibodies (P<0.05). Furthermore, one mother of an autistic child (3 %) had persistent APL antibodies., Conclusion: ASD had no significant relation with the presence of APL antibodies., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

The most common thyroid abnormality among Down syndrome (DS) children corresponds to a mildly elevated TSH, with T4 decreased or in the normal range and thyroid hypoplasia, from the neonatal period onward, which aggravate their mental impairment. Transgenic Dyrk1A mice, obtained by bacterial artificial chromosome engineering (mBACTgDyrk1A), have 3 copies of the Dyrk1A gene. The objective is to determine whether this transgenic Dyrk1A (Dyrk1A(+/++)) mouse is an adequate murine model for the study of thyroid dysgenesis in DS. Embryonic thyroid development from embryonic day 13.5 (E13.5) to E17.5 was analyzed in wild-type (WT) and Dyrk1A(+/++) mice by immunofluorescence with anti-Nkx2-1, anti-thyroglobulin, and anti-T4 antibodies, markers of early thyroid development, hormonogenesis, and final differentiation, respectively. The expression of transcription factors Nkx2-1, Pax8, and Foxe1 involved in thyroidogenesis were studied by quantitative RT-PCR at the same embryonic stages. We then compared the adult phenotype at 8 to 12 weeks in Dyrk1A(+/++) and WT mice for T4 and TSH levels, thyroidal weight, and histological analysis. Regarding thyroidal development, at E15.5, Dyrk1A(+/++) thyroid lobes are double the size of WT thyroids (P = .01), but the thyroglobulin stained surface in Dyrk1A(+/++) thyroids is less than a third as large at E17.5 (P = .04) and their differentiated follicular surface half the size (P = .004). We also observed a significant increase in Nkx2-1, Foxe1, and Pax8 RNA levels in E13.5 and E17.5 Dyrk1A(+/++) embryonic thyroids. Dyrk1A(+/++) young adult mice have significantly lower plasma T4 (2.4 ng/mL versus WT, 3.7 ng/mL; P = 0.019) and nonsignificantly higher plasma TSH (114 mUI/L versus WT, 73mUI/L; P = .09). In addition, their thyroids are significantly heavier (P = .04) and exhibit large disorganized regions. Dyrk1A overexpression directly leads to thyroidal embryogenetic, functional and morphological impairment. The young adult thyroid phenotype is probably a result of embryogenetic impairment. The Dyrk1A(+/++) mouse can be considered a suitable study model for thyroid dysgenesis in DS.

Background: Adequate protein nutrition could be used to limit gradual body protein loss and improve protein anabolism in the elderly., Objective: We tested the hypothesis that an uneven protein feeding pattern was more efficient in improving protein anabolism than was an even pattern., Design: After a controlled period, 15 elderly women (mean age: 68 y) were fed for 14 d either a pulse diet (n = 7), providing 80% of the daily protein intake at 1200, or a spread diet (n = 8), in which the same daily protein intake was spread over 4 meals. Both diets provided 1.7 g protein x kg fat-free mass (FFM)(-1) x d(-1). Protein accretion and daily protein turnover were determined by using the nitrogen balance method and the end product method (ammonia and urea) after an oral dose of [15N]glycine., Results: Nitrogen balance was more positive with the pulse than with the spread diet (54 +/- 7 compared with 27 +/- 6 mg N x kg FFM(-1) x d(-1); P < 0.05). Protein turnover rates were also higher with the pulse than with the spread diet (5.58 +/- 0.22 compared with 4.98 +/- 0.17 g protein x kg FFM(-1) x d(-1); P < 0.05), mainly because of higher protein synthesis in the pulse group (4.48 +/- 0.19 g protein x kg FFM(-1) x d(-1)) than in the spread group (3.75 +/- 0.19 g protein x kg FFM(-1) x d(-1)) (P < 0.05)., Conclusion: A protein pulse-feeding pattern was more efficient than was a protein spread-feeding pattern in improving, after 14 d, whole-body protein retention in elderly women.

Our aim was to analyze mechanisms involved in the adaptation of protein metabolism to food deprivation and refeeding in adult rats. Twelve-month-old rats, which had been food-deprived for 113 h and refed for 6 h, were injected subcutaneously with a flooding dose of valine (with 50% [1-13C]-L-valine) to measure in vivo protein synthesis in tibialis anterior, soleus and liver. Protein and RNA contents were also measured. In both muscles, protein mass was maintained during food deprivation. Due to a drop in protein synthetic capacity (Cs), total and myofibrillar protein synthesis rates were reduced in food-deprived rats and were not stimulated by a 6-h refeeding. In contrast, protein levels were maintained lower than RNA levels in liver during food deprivation, and Cs was higher than in fed rats. Protein synthesis rates and ribosomal efficiency were reduced in food-deprived rats. Due to maintenance of protein synthetic capacity, there was a rapid stimulation of liver protein synthesis with refeeding, which induced a significant rise in protein mass (also related to an inhibition of protein degradation). In conclusion, coordinated responses of liver and muscles allowed a sparing of muscle proteins during food deprivation and a rapid recovery of liver proteins during refeeding. Control of ribosome quantity could play a critical role in these adaptations in tissue protein synthesis in adult rats.

An automated method for the determination of plasma free amino groups is described. The analysis is performed on a discrete computerized analyzer after plasma deproteinization using trichloracetic acid. The method is based on the formation of a complex between terminal NH2 radicals and 2,4,6-trinitrobenzene sulfonate (TNBS). The method is accurate (coefficient of variation = 2%), linear over a range of 0.2-7 mM/l and requires small analytic volumes; it also correlates well in the bovine with results from standard liquid chromatography (r = 0.953). With this method a single operator can determine free amino group contents of 50 samples per h.

The fractional contributions (FC) of threonine to glycine and 2-ketobutyrate (KB) fluxes in fed pigs have been assessed by the constant infusion of L-[1-13C]-threonine. The analysis of the enantiomeric purity of labeled threonine by gas chromatography/mass spectrometric (GC/MS) analysis is reported as the N-TFA isopropyl ester derivative. The commercially available [1-13C]threonine comprised 98.7% of the L-enantiomer, enriched at 99 atom percentage excess (APE), and 1.3% of L-allo-threonine contaminant, also enriched at 99 APE. The enantiomeric purity of threonine in plasma of pigs infused for 10 h with [1-13C]threonine showed that the L-allo contaminant did not accumulate. The t-butyl dimethylsilyl derivatives of threonine, glycine, and 2-aminobutyrate (ABA) were used to measure the enrichment of these compounds in plasma and liver samples by GC/MS/selected ion monitoring analysis. Analyses were performed on between 1 and 5 nmol of each amino acid extracted from biological fluids and a 1:10 split injection. GC/MS parameters were assessed with standards at similar quantities and found to be satisfactory; e.g., injection of 1-10 nmol of glycine did not significantly alter the slope and the precision of the standard curve. The coefficient of variation of enrichment determination was less than 10% for standards enriched at 0.4 APE or more and biological samples enriched at 0.6 APE or greater. Within-animal coefficients of variation for four plasma samples obtained at equal intervals between 8 and 10 h of [1-13C]threonine infusion were 4, 21, and 24% for threonine, ABA, and glycine, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Three preruminant calves were fitted with catheters in portal and hepatic veins and in a mesenteric artery. Two electromagnetic flowmeter probes were clipped around the portal vein and the hepatic artery. The calves were fed either a diet with a low (L) or a high (R) abomasal emptying rate for dietary proteins. Blood flow and free amino acid levels in plasma (P) and blood (S) were determined before the morning meal and during the following 7 h. In the portal vein, for most amino acids P/S ratios were correlated to the net amino acid balance of the digestive tract measured in plasma. By contrast in the hepatic vein, these ratios were mainly correlated to hepatic balance measured in whole blood. Correlations between digestive tract and hepatic balance calculated using either plasma or whole blood pool were different for some amino acids. This suggests that amino acid exchange between plasma and blood cells is low and absorbed amino acids are mainly transported to the liver by plasma, whereas whole blood rather than plasma is concerned in amino acid exchanges in the liver.

A study was made on protein metabolism and hormonal changes following birth in newborn lambs fed amino acids alone or in combination with lactose. Eight newborn lambs taken from their mother immediately after birth were fed hourly for 8 h, either with a solution of peptides and free amino acids obtained by mild hydrolysis of whey proteins (4 lambs; diet AP) or with the same solution + lactose (4 lambs; diet APL). L-[4,5-3H] leucine was continuously perfused into a jugular vein for 6 h when the lambs were 2 h 30 min old. Plasma glucose and insulin levels increased after birth in APL lambs whereas they decreased in the AP; these differences were significantly different. Plasma cortisol levels remained unchanged throughout the experiment. Free essential amino acid levels did not vary when lambs were older than 4.5 h; they depended on the corresponding amino acid intakes. Plasma free threonine, valine, isoleucine, leucine, tyrosine and lysine were lower in APL than in AP lambs. The plasma leucine irreversible loss and leucine oxidation were higher in AP than in APL lambs. The plasma flux of leucine from whole body protein breakdown was lower in APL than in AP lambs inasmuch as the plasma flux of dietary leucine may be estimated by the amounts of leucine ingested in both cases. No significant difference was found for the fractional synthesis rates of tissue proteins such as liver, skin, skeletal muscle, lung, brain and whole body. These rates for skin, muscle and whole body were close to those previously measured in colostrum fed lambs. The increase in whole body protein accretion resulting from lactose feeding in combination with amino acids seemed to result from a decreased protein breakdown that could be mediated by the insulin response.

The present work was carried out to evaluate the kinetic parameters of glucagon in growing rats divided into three groups: T, H and E. Group T (Control group) was fed a control diet (crude protein: 11.8%). Groups H and E received a high protein diet (crude protein: 19%) distributed in either equal (Group H) or restricted amounts (Group E) with respect to the control. Thus, the main characteristic of Group H was the high level of protein intake (+ 68%) when Group E rats underwent a moderate increase in protein intake but a striking caloric deprivation (-25%). In all cases, the animals were fed a meal every 4 hours. The kinetic parameters of glucagon metabolism were estimated from the plasma disappearance curves of 125I-glucagon for five minutes following a pulse injection of purified 125I-glucagon (1 muCi, about 3.8 ng/100 g BW). Plasma 125I-glucagon was measured after gel filtration of plasma on Biogel P-10. Tissue radioactivity (mainly liver and kidneys) was recorded seven minutes after 125I-glucagon injection. The results showed that the plasma 125I-glucagon level was higher in Group H than in the other groups 1 min after the injection. At all other times (2, 3.5 and 5 min) it was similar in all groups. 125I-glucagon was rapidly cleared from plasma and rapidly taken up by the liver and kidneys. In the 3 experimental groups, mean half-life and metabolic clearance rate were estimated to be 2 min and 6 ml/min/100 g BW, respectively. Excess protein intake resulted in a reduction in the apparent initial distribution volume of 125I-glucagon without modifying significantly its turn-over rate and metabolic clearance rate. Kidneys and liver (6% BW) accounted for about 20% of the 125I-glucagon uptake by tissues 7 min after injection. Group H kidneys and liver were more labelled than in other groups. These results suggest that increased protein intake (without further caloric deprivation) can induce some changes in glucagon metabolism which could partially contribute to the increase in glucagonemia usually observed in animals fed high protein diets.