Measurements of Myofibrillar Protein Breakdown in Newborn Human Infants

1982 ◽  
Vol 63 (5) ◽  
pp. 421-427 ◽  
Author(s):  
J. L. Burgoyne ◽  
F. J. Ballard ◽  
F. M. Tomas ◽  
A. Dobozy ◽  
A. H. MacLennan ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Degradation Rate ◽  
Myofibrillar Protein ◽  
Full Term ◽  
Protein Breakdown ◽  
Excretion Ratio ◽  
Human Infants ◽  
Term Infants ◽  
Breakdown Rate ◽  
Ion Exchange Separation

1. Myofibrillar protein breakdown was calculated from the urinary excretion ratio of Nτ-methylhistidine (3-methylhistidine) to creatinine in newborn premature and full-term infants. Representative values were obtained from single voidings provided that the infant's metabolic status was stable. 2. Nτ-Methylhistidine in infant urine was measured by a rapid Auto Analyser method and shown to give similar values to those obtained by ion-exchange separation techniques. 3. The molar excretion ratio of Nτ-methylhistidine to creatinine averaged 0·0159 in urine samples obtained within 12 h after birth. A similar ratio was found in amniotic fluid collected at birth. It is argued that this ratio does not reflect a low rate of myofibrillar protein breakdown in the foetus, but rather a more effective transplacental passage of Nτ-methylhistidine than of creatinine. 4. The urinary ratio increased during the first 2 days after birth to a plateau at 0·0372. This represents a myofibrillar protein degradation rate of 3·40% day−1 in full-term infants. 5. The molar excretion ratio during the period 40–120 h after birth increased in premature infants and reflects a fractional degradation rate of 5·34% day−1 in those infants weighing less than 1 kg at birth. 6. Lower excretion ratios were found in some infants of diabetic mothers and in athyroid infants. 7. The urinary excretion ratio of Nτ-methylhistidine to creatinine is presented as a useful method for evaluating the breakdown rate of myofibrillar protein in neonates and can be applied to a number of abnormal nutritional or hormonal states.

Growth Hormone-Induced Changes in Myofibrillar Protein Breakdown in Hypopituitary Children

1983 ◽  
Vol 64 (3) ◽  
pp. 315-320 ◽  
Author(s):  
F. J. Ballard ◽  
J. L. Burgoyne ◽  
F. M. Tomas ◽  
J. L. Penfold
Keyword(s):  
Growth Hormone ◽  
Hormone Treatment ◽  
Myofibrillar Protein ◽  
The Body ◽  
Protein Breakdown ◽  
Older Children ◽  
Breakdown Rate ◽  
Fractional Rate ◽  
Excretion Rates ◽  
Induced Changes

1. Creatinine and Nτ-methylhistidine excretion rates have been measured in 13 hypopituitary children to calculate the body muscle contents and rates of myofibrillar protein breakdown. Analyses have been made during periods of growth hormone withdrawal and subsequent administration. 2. The creatinine excretion rate was lower in the hypopituitary children, indicating a lower muscle content per kg body weight. This difference persisted even in children who had received growth hormone for several years. 3. Excretion of Nτ-methylhistidine was reduced by the administration of growth hormone. 4. The fractional breakdown rate of myofibrillar protein, as calculated from the Nτ-methylhistidine to creatinine molar excretion ratio, averaged 1.76%/day in the four youngest children during growth hormone withdrawal. This was significantly higher than for control children of a similar age (P < 0.02) and was reduced to the normal rate of 1.47%/day by growth hormone administration. 5. in older children the fractional rate of myofibrillar protein degradation remained in the normal range irrespective of growth hormone treatment. 6. These results are discussed in the context of the anabolic effects of growth hormone on muscle being partly explained by its action to decrease rates of protein breakdown.

URINARY EXCRETION OF PHENOLIC AND INDOLIC COMPOUNDS, METACATECHOLAMINES, AND VMA BY FULL-TERM AND PREMATURE INFANTS

PEDIATRICS ◽  
1968 ◽  
Vol 41 (4) ◽  
pp. 777-783
Author(s):  
Demetre Nicolopoulos ◽  
Anthony Agathopoulos ◽  
Calliope Danelatou-Athanassiadou ◽  
Marianthi Bafataki
Keyword(s):  
Urinary Excretion ◽  
Phenolic Acids ◽  
Premature Infants ◽  
Homogentisic Acid ◽  
Full Term ◽  
Term Infants ◽  
Catabolic Pathways ◽  
Indolic Compounds

The 24-hour urinary excretion of phenolic and indolie compounds, metacatechol-amines, and VMA by full-term and premature infants on their first and fifteenth days of life was studied. The presence of metabolites from all three main catabolic pathways of tryptophan was noted in both groups of infants. 3-indole-acetic and 3-indole-propionic acids were present on the first day of life in the urine of full-term infants, but they were absent on the fifteenth day. Twenty phenolic acids were observed in both groups of infants, but their excretion varied a great deal. Homogentisic acid was not excreted on the first day of life of full-term and premature infants, but it was found in the urine of full-term infants on the fifteenth day of life. The variations of excretion of VMA generally followed that of metacatecholamines. The excretion of VMA by the premature infants on their fifteenth day of life is four- to fivefold that of the first day and reaches adult levels, in contrast to the moderate decrease of VMA excretion of the fuil-term infants on the fifteenth day. The degree of maturation of the enzymic systems involved is discussed as a probable cause of these variations.

Light deprivation increases plasma levels of melatonin during the first 72 h of life in human infants

1993 ◽  
Vol 129 (5) ◽  
pp. 442-445 ◽  
Author(s):  
F Jaldo-Alba ◽  
A Muñóz-Hoyos ◽  
A Molina-Carballo ◽  
JA Molina-Font ◽  
D Acuña-Castroviejo
Keyword(s):  
Pineal Gland ◽  
Continuous Light ◽  
Full Term ◽  
Light Deprivation ◽  
Suprachiasmatic Nuclei ◽  
Melatonin Secretion ◽  
Human Infants ◽  
Term Infants ◽  
Term Neonates ◽  
Plasma Bilirubin

The development of rhythmic melatonin secretion in full-term neonates seems to occur at about 12 weeks of age, but activity of the pineal gland from 1 to 12 weeks of age is not well documented. To determine whether the pineal gland actively secretes melatonin and reacts to photoperiodic information during this period, we analyzed 45 full-term infants exposed to continuous artificial light during 24, 48 and 72 h after birth for treatment of hyperbilirubinemia. During this light treatment, the eyes of the neonates were completely covered to avoid damage, thus the infants were under continuous light deprivation. Phototherapy significantly decreased plasma bilirubin during treatment. With regard to pineal gland activity, the shortest period of light deprivation tested, 24 h, significantly increased plasma melatonin levels from 152.66±11.57 to 244.86±19.49 ng/l (mean±sem; p<0.001). The other periods tested, 48 and 72 h of light deprivation, led to similar percentages of melatonin stimulation. These results suggest that the pineal gland of neonates, before displaying rhythmic metabolic activity, is sensitive to changes in environmental illumination, indicating maturity of some features of suprachiasmatic nuclei function.

scholarly journals Regulation of total and myofibrillar protein breakdown in rat extensor digitorum longus and soleus muscle incubated flaccid or at resting length

1990 ◽  
Vol 267 (1) ◽  
pp. 37-44 ◽  
Author(s):  
P O Hasselgren ◽  
M Hall-Angerås ◽  
U Angerås ◽  
D Benson ◽  
J H James ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Total Protein ◽  
Extensor Digitorum Longus ◽  
Myofibrillar Protein ◽  
Extensor Digitorum ◽  
Protein Breakdown ◽  
Breakdown Rate ◽  
Net Production ◽  
Breakdown Rates

The present study characterized total and myofibrillar protein breakdown rates in a muscle preparation frequently used in vitro, i.e. incubated extensor digitorum longus (EDL) and soleus (SOL) muscles of young rats. Total and myofibrillar protein breakdown rates were assessed by determining net production by the incubated muscles of tyrosine and 3-methylhistidine (3-MH) respectively. Both amino acids were determined by h.p.l.c. Both total and myofibrillar protein breakdown rates were higher in SOL than in EDL muscles and were decreased by incubating the muscles maintained at resting length, rather than flaccid. After fasting for 72 h, total protein breakdown (i.e. tyrosine release) was increased by 73% and 138% in EDL muscles incubated flaccid and at resting length respectively. Net production of tyrosine by SOL muscle was not significantly altered by fasting. In contrast, myofibrillar protein degradation (i.e. 3-MH release) was markedly increased by fasting in both muscles. When tissue was incubated in the presence of 1 munit of insulin/ml, total protein breakdown rate was inhibited by 17-20%, and the response to the hormone was similar in muscles incubated flaccid or at resting length. In contrast, myofibrillar protein breakdown rate was not altered by insulin in any of the muscle preparations. The results support the concepts of individual regulation of myofibrillar and non-myofibrillar proteins and of different effects of various conditions on protein breakdown in different types of skeletal muscle. Thus determination of both tyrosine and 3-MH production in red and white muscle is important for a more complete understanding of protein regulation in skeletal muscle.

N τ-Methylhistidine Excretion and Myofibrillar Protein Breakdown in Patients Receiving Intravenous or Enteral Nutrition

1980 ◽  
Vol 59 (3) ◽  
pp. 211-214 ◽  
Author(s):  
I. B. Holbrook ◽  
E. Gross ◽  
P. J. Milewski ◽  
K. Shipley ◽  
M. H. Irving
Keyword(s):  
Enteral Nutrition ◽  
Muscle Protein ◽  
Myofibrillar Protein ◽  
Protein Breakdown ◽  
Breakdown Rate ◽  
Creatinine Excretion ◽  
Non Invasive ◽  
Breakdown Rates ◽  
Invasive Measurement

1. Nτ-Methylhistidine, nitrogen and creatinine were measured in the urine of 10 volunteers on normal and meat-free diets and in 10 vegetarians, and compared with the results from the urine of eight patients with intestinal fistulae on intravenous or enteral nutrition containing no meat. The values obtained were used to calculate fractional breakdown rate of myofibrillar protein. 2. There was a significant fall in the excretion of Nτ-methylhistidine and creatinine and in apparent fractional breakdown rates after 2 days on a meat-free diet. 3. One of the patients had lower, and two of the patients had higher, fractional breakdown rates compared with the vegetarians. 4. Nτ-Methylhistidine and creatinine excretion-5-be a useful and non-invasive measurement of myofibrillar protein degradation in patients on meat-free diets. Firm conclusions cannot, however, be drawn without confirmatory, direct measurement of the breakdown rates of muscle protein in vivo.

Ntau;-methylhistidine excretion is a valid index of myofibrillar protein breakdown in the guineapig (Cavia porcellus)

2001 ◽  
Vol 35 (4) ◽  
pp. 374-378
Author(s):  
P. F. Rogers ◽  
F. M. Tomas
Keyword(s):  
Urinary Excretion ◽  
Chromatographic Analysis ◽  
Myofibrillar Protein ◽  
Intravenous Dose ◽  
Cavia Porcellus ◽  
Protein Breakdown ◽  
Total Recovery ◽  
Valid Index ◽  
Almost All ◽  
Cumulative Excretion

The recovery of radioactivity in the urine of guineapigs following a bolus intravenous dose of chromatographically pure 14C-Nτ-methylhistidine was measured in order to test whether the excretion of Nτ-methylhistidine (Nτ-MH) is a valid index of myofibrillar protein breakdown in these animals. Four male and four female guineapigs were dosed and after 7 days, 91.65 ± 2.82% and 3.58 ± 0.91% of injected radioactivity was recovered in the excreta and tissues, respectively. The average total recovery of 95.2 ± 3.0% was not significantly different from 100%. Male guineapigs excreted the radioactivity more slowly than females (70% of the dose excreted within 74 h vs 39 h, respectively) but cumulative excretion at 7 days was the same for each sex. Chromatographic analysis of the urine showed almost all of the radioactivity to be associated with a single peak corresponding to Nτ-MH, indicating a lack of significant metabolism. These data show that although the clearance of 14C-Nτ-MH is slower than in rats or humans the urinary excretion of Nτ-MH is a valid index for myofibrillar protein degradation in the guineapig.

scholarly journals Preterm and full term infant vocalization and the origin of language

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
D. Kimbrough Oller ◽  
Melinda Caskey ◽  
Hyunjoo Yoo ◽  
Edina R. Bene ◽  
Yuna Jhang ◽  
...  
Keyword(s):  
Intensive Care ◽  
Neonatal Intensive Care ◽  
Modern Human ◽  
Term Infant ◽  
Full Term ◽  
Linguistic Features ◽  
Human Infants ◽  
Term Infants ◽  
Infant Vocalization ◽  
Origin Of Language

Abstract How did vocal language originate? Before trying to determine how referential vocabulary or syntax may have arisen, it is critical to explain how ancient hominins began to produce vocalization flexibly, without binding to emotions or functions. A crucial factor in the vocal communicative split of hominins from the ape background may thus have been copious, functionally flexible vocalization, starting in infancy and continuing throughout life, long before there were more advanced linguistic features such as referential vocabulary. 2–3 month-old modern human infants produce “protophones”, including at least three types of functionally flexible non-cry precursors to speech rarely reported in other ape infants. But how early in life do protophones actually appear? We report that the most common protophone types emerge abundantly as early as vocalization can be observed in infancy, in preterm infants still in neonatal intensive care. Contrary to the expectation that cries are the predominant vocalizations of infancy, our all-day recordings showed that protophones occurred far more frequently than cries in both preterm and full-term infants. Protophones were not limited to interactive circumstances, but also occurred at high rates when infants were alone, indicating an endogenous inclination to vocalize exploratorily, perhaps the most fundamental capacity underlying vocal language.

Respiratory response to airway occlusion in infants: sleep state and maturation

1976 ◽  
Vol 41 (5) ◽  
pp. 634-638 ◽  
Author(s):  
I. D. Frantz ◽  
S. M. Adler ◽  
I. F. Abroms ◽  
B. T. Thach
Keyword(s):  
Full Term ◽  
Respiratory Response ◽  
Sleep State ◽  
Human Infants ◽  
Term Infants ◽  
Compensatory Response ◽  
Airway Occlusion ◽  
Chemical Stimuli ◽  
Thoracic And Abdominal ◽  
Respiratory Movements

The progressive respiratory response to occlusion of the airway at FRC was measured in a group of full-term and premature human infants. The sleep state of the full-term infants was shown to affect the response primarily through variations in the phase of thoracic and abdominal movements. The weakest responses were seen in those infants who demonstrated parodoxical respiration prior to occlusion. Most infants developed paradoxical respiratory movements after occlusion, but this did not affect the strength of the load-compensatory response. An increase in response related to both gestationaland postnatal age was observed. This increase could not be accounted for byvariations in the amount of paradoxical and in-phase respiration and thus may represent an increase in the sensitivity of infants to chemical stimuli with maturation.

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