The individual development of circadian temperature rhythm in infants

Abstract

The aim of this study was to explore the individual development of the circadian rhythm of human body temperature. Dailyperiodicchanges of body temperature were examined longitudinally in four infants from 3 to 18 months of age. At the 3rd month of life, the day‐night rhythm of the body temperature was obscure but at the 6th month it became moreevident. From the 12th month on, the circadian temperature rhythm with phase similar to that of the adult was discerned. However, the amplitude in circadian rhythm was significantly larger in children between 6 and 18 months of age than in the adult. These findings suggest that the adult type of circadian rhythm of human body temperature is established during the first year of life with regard to phase but not to amplitude.     

Haptoglobin expression and activity during coronary collateralization

Coronary collateral development relies on the coordinated secretion of growth factors. However, alone they are insufficient for permanent collateral growth. We utilized proteomics to identify other important proteins in the extracellular environment that could facilitate collateralization. Chronically instrumented dogs developed coronary collaterals by the repetitive occlusion method. Subendocardial (0.19 +/- 0.04, 0.27 +/- 0.06, 0.48 +/- 0.10, and 0.81 +/- 0.11 ml x min(-1) x g(-1) on days 1, 7, 14, and 21, respectively) and subepicardial (0.14 +/- 0.01, 0.36 +/- 0.06, 0.51 +/- 0.07, and 0.71 +/- 0.08 ml x min(-1) x g(-1) on days 1, 7, 14, and 21, respectively) blood flow increased in animals subjected to repetitive occlusion. Sham animals exhibited no changes in blood flow. Myocardial interstitial fluid (MIF) from both groups was analyzed by two-dimensional electrophoresis with matrix-assisted laser desorption/ionization time-of-flight identification. The acute-phase protein haptoglobin was identified in the group subjected to repetitive occlusion. ELISA of MIF showed haptoglobin to be elevated at all time points of collateral development compared with sham, with maximal production on day 7. Purified haptoglobin dose dependently stimulated endothelial cells to form tubes and vascular smooth muscle cells to migrate. Purified haptoglobin did not stimulate proliferation of either cell type. The relative contribution of haptoglobin to the chemotactic properties of MIF was tested using a neutralizing antibody. Neutralized MIF could not stimulate smooth muscle cells to migrate at any time during collateral development. Endothelial cell tube formation was inhibited after the midpoint of collateralization. Therefore, the acute-phase protein haptoglobin plays a critical role during coronary collateralization.     

Serum haptoglobin type and liver cirrhosis.

Haptoglobin phenotypes were studied by a polyacrylamide gel electrophoresis on 200 blood donors and 105 patients with liver cirrhosis, of which 79% belonged to non-alcoholic etiology. Though no difference of haptoglobin types could be found between blood donors with positive and negative hepatitis B antigen, the cirrhois patients had an excess haptoglobin gene 1. The patients with haptoglobin gene 1 were associated with severe liver dysfunction. Since the family pedigrees of the patients with type 1--1 excluded individuals with type 2--2, the phenotypes seemed to be stable in the cirrhotic process. The possibility that the haptoglobin 2 gene offered resistence to the non-alcoholic cirrhosis was discussed.     

Postnatal changes in 2,3-diphosphoglycerate (2,3-DPG) content of calf erythrocytes

In 82 calves, 22 adult cows and 10 fetuses the 2,3-DPG level was determined in the erythrocytes. The lowest level was found in cows (1.13 microM/g haemoglobin, on the average), and in calves aged 35 days or more. In the foetuses the mean 2,3-DPG concentration in the erythrocytes was 4.98 microM/g Hb and it was higher that that in the erythrocytes of cows, the oldest foetuses and calves during the first two days of postnatal life. During 5 weeks of postnatal life the changes taking place in 2,3-DPG concentration could be divided into two periods: period I or the period of increase covering the first 6 days of life, with a characteristic rise in the concentration of this component from 1.37 to 15.80 microM/g Hb, and period II or the period of decrease lasting from the 6th to the 35th day of life. In period II two phases could be discerned, the first phase lasting from the 6th to the 10th day with a steep fall of 2,3-DPG level from 15.80 to 4.58 microM/g Hb, and the second phase from the 10th to the 35th day of life in which the level of 2,3-DPG reached slowly the value found in adult cows. A comparison of oxygen affinity of haemoglobin in calves aged 6 days, which was composed of about 80% of fetal haemoglobin and about 20% of adult haemoglobin, and in adult cows, which contained exclusively adult haemoglobin, showed that the oxygen-binding capacity of haemoglobin was lower in calves.     

Subcellular distribution and postnatal development of cholinergic marker proteins in the striatum of rat

The distribution of muscarinic cholinergic receptors, choline acetyl-transferase and acetylcholinesterase activities were measured in subcellular fractions of the rat striatum on the 5th and 15th days postnatally and in adulthood. The receptor density in the striatum of 5 and 15-day-old rats was 15%, respectively, of the adult value. Similar increases of the receptors could be detected in the synaptosomal and microsomal fractions in the postnatal life of rat. The activity of choline acetyltransferase on the same days was 15% and 28%. In the subcellular fractions, the enzyme activity was the highest in the microsomal fraction on both the 5th and 15th days postnatally. The activity of acetylcholinesterase in the homogenate was 6% of the adult value in the 5-day-old rat striatum, while in the synaptosomal fraction it was 11% and 47% of the adult value on the 5th and 15th days, respectively. Our results show that the development of the muscarinic cholinergic receptors precedes that of the two cholinergic enzymes in both 5 and 15-day-old rat striatum. This may suggest an early perikaryonal synthesis and the fast translocation of receptors to the axon terminals during ontogenetic development.     

Cytofluorimetric study of the content of glycogen and its fractions in rat liver cells in the course of the 1st week of postnatal ontogeny]

A cytofluorometric study of the total glycogen and its fractions in rat liver cells using the fluorescent PAS reaction was made during 1--7 days of the postnatal development. It was established that glycogen content was small on the first two days of development. The glycogen content increases only on the third day after birth. The glycogen of the rat liver cells during a first week of the postnatal development is different from that detected in adult liver cells in two aspects: in 3 day old hepatocytes soluble and stable glycogen fractions are equal, while in adult rat liver cells the former makes 80--90%; during the first week of the postnatal development, the stable fraction of rat liver cell is more labile, while in the adult rat liver the soluble fraction of glycogen is more labiles.     

Immunoreactive insulin and insulin-like activity of the blood in ontogenesis of the hen]

Studies have been made on immunoreactive insulin (IRI) and insulin-like activity (ILA) in the blood serum of chick embryos (from the 10th day of incubation), chicks and adult hens up to 1 year old. It was shown that IRI content of embryonic blood is relatively low and remains approximately constant during incubation. During postnatal ontogenesis, the level of IRI increases, the increase being most significant at the 1st day after hatching and between the 2nd and the 5th months. With respect to IRI level, 5-month chicks are similar to adult hens. Being assayed by the method of isolated epididymal rat fat, ILA was not found in the blood serum of chick embryos. It was observed in all test samples only from the 30th day after hatching. It is suggested that at this period of postnatal life, some factors are formed in the blood which increase ILA without changes of the insulin content of the blood. After the 30th day, no evident shifts were observed in ILA, although it reached maximum in adult hens. By absolute values, ILA of the blood in chicks was several times higher than the corresponding levels of IRI.     

Postnatal changes in the amount of acetylcholine in the atrial tissue of the albino rat heart.

Changes in the acetylcholine (ACh) content and concentration in the atrial tissue of albino rats between the third day of postnatal life and adulthood were studied. The ACh content (ng in whole atria) rose during the whole of the period in question, from 5.6 ng at 3--4 days to 307.5 ng in adult rats. The ACh concentration (micrograms/g fresh tissue) rose up to the 53rd day after birth, when it attained adult values. The fastest increase in both the ACh content and concentration was observed between the 10th and the 17th postnatal day, when it amounted to over 46% of the total concentration increase between the third day of life and adulthood.     

Biology of Triatoma flavida Neiva, 1911 (Hemiptera: Reduviidae) under laboratory conditions

The complete life cycle of Triatoma flavida, weekly fed on hens, was studied at 28+/-2 degrees C and 80+/-10% RH. Aspects related to hatching, life span, mortality and feeding behavior for each stage of its life cycle were evaluated. The hatching rate observed for 100 eggs was 93% with an average incubation period of 27.2 days. Sixty-two nymphs completed the cycle and the mean egg to adult development time was 230.4 days. Mean duration of 1st, 2nd, 3rd, 4th and 5th instar nymphs was 22.1, 25.3, 36.7, 49.7 and 69.4 days, respectively. The number of blood meals on each nymphal stage varied from 1 to 7. The mortality rate was 6.5% for NI, 23% for NIII and 7.5% for NV nymphs. Mean number of laid eggs per female was 283.1. Adult survival rates were 344.8 +/- 256.4 days for males and 285.3 +/- 201.8 days for females.     

Influence of prenatal malnutrition on later body-weight gain in guinea pigs]

In prenatally underfed guinea pigs the following data were obtained: 1. On the 1st day of life the mean body weight of 18 underfed animals was significantly reduced as compared to that of 18 control animals. This difference was not compensated by postnatal feeding ad libitum but persisted up to the 36th week of life (day of sacrificing). 2. The mean food intake per day estimated over 10 days during the 5th month of life was also significantly diminished in the prenatally underfed animals. 3. A significant positive correlation was found between the body weight at birth and the adult body weight, adult body length and adult body weight/body length, when the parameters of the experimental plus control animals were evaluated together. These findings suggest that in guinea pigs, which are born in a relatively mature stage, the prenatal nutrition can influence body weight, body length and body weight/body length ratio as well as food intake in adulthood.     

Postnatal changes in the activities of acetylcholinesterase and butyrylcholinesterase in rat heart atria

Postnatal development of the activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in rat heart atria has been investigated with the use of 1.5-bis (allyldimethylammoniumphenyl) pentane-3-dibromide (BW 284 C51) as a selective inhibitor of AChE. Total cholinesterase activity (mumol acetylthiocholine hydrolysed X g-1 per hour) increased from 218 on the 1st day after birth to 426 on the 30th day and diminished to 340 in adult rats. The activity of AChE (mumol acetylthiocholine hydrolysed X g-1 per hour) underwent more dramatic changes, increasing more than 4-fold during the first month of life, from 13 on the 1st to 58 on the 30th day of life and then decreasing to 42 in adult rats. The proportion of AChE on total cholinesterase activity increased from 6% on the 1st day to 12-15% in animals aged 24 days and more. Since AChE is known to be specifically involved in the termination of the action of acetylcholine in the sinoatrial node, the observed postnatal changes in its activity are likely to play a role in the postnatal development of cardiac parasympathetic control.     

Cytosolic sialidase from the nerve endings of developing rat forebrain

The developmental profile of cytosolic sialidase from the nerve ending and the nerve ending-free compartments of rat forebrain was studied from birth to 150 days. Soluble extracts containing the cytosol from nerve endings and nerve ending-free tissue were separately prepared; the recovery of cytosol in the two extracts was followed by assaying lactate-dehydrogenase. In both cytosolic extracts the content of sialidase and lactate-dehydrogenase had a marked and progressive enhancement from the 5th to the 20th day of life and then maintained a constant level through adult life. However the rate of lactate-dehydrogenase and sialidase increase in the two cytosolic compartments was different. Lactate-dehydrogenase increased at a very similar rate in the two cytosols. Instead the rate of sialidase increase was greater in the cytosol from nerve endings from the 5th to the 10th day of life, and, inversely, in the cytosol from nerve ending-free tissue from 10 to 20 days. Between the 5th and 10th day of life the nerve ending cytosol underwent an enrichment of sialidase which was several times higher than that of lactate-dehydrogenase; in the other periods of forebrain development sialidase and lactatedehydrogenase moved in parallel.The variations with age of cytosolic sialidase from the nerve ending-free tissue seemed to follow the overall process of brain development. The nerve ending soluble sialidase would more specifically reflect formation of synaptic junctions in some brain regions in a well defined period of brain maturation.     

The ultrastructure of the developing neural lobe

Summary The ultrastructure of the developing neural lobe of rats was studied. The results revealed three periods in its development. The first period lasts till the 17th day of fetal life. At its beginning the anlage of the neural lobe is formed as a mass of cells very similar in appearance and in connection with the subependymal cells of the future median eminence. During the first period the cells of the anlage differentiate into pituicytes, and the penetration of the first nerve fibres and blood vessels among them is seen. The second period is from the 18th day of fetal life till one month after birth. At its beginning the first signs of neurosecretory activity were detected. During the period increasing numbers of neurosecretory fibres penetrate into the neural lobe, and the pituicytes show morphological signs characteristic of active cells. An increase in the functional activity of the neural lobe is also detected. The third period is from the end of the 1st till the end of the third month. During this period the development of the neural lobe proceeds and at the end it has the appearance of the adult gland. During this period the pituicytes gradually lose the signs of activity and at the end of the period they look like those observed in adult animals. Considering the results from the study, together with some data from previous investigations it is suggested that the pituicytes exert some stimulating and regulative influences on the process of neurosecretion in the neural lobe.Research fellow of the Alexander von Humboldt Foundation.     

Postnatal development of postganglionic parasympathetic neurones in the heart of the albino rat.

Electrical stimulation of the sinoatrial node region of isolated atria in medium containing physostigmine (0.1 micrograms/ml) produces a negative chronotropic effect whose intensity and duration depend mainly on the amount of acetylcholine released from postganglionic parasympathetic fibres endings. This technique was used to study functional maturation of the given neurones during postnatal development of albino rats. Preparations from animals of different ages were stimulated with 2-second bursts of rectangular pulses (frequency 50 Hz, pulse duration 0.02 ms, voltage 22.5--27.5 V) and frequency changes of the preparation were registered by recording extracellular action potentials. At 10 days the negative chronotropic effect is very weak and at 15 days it is only slightly stronger, but at 18 days it is almost the same as in adult animals. At 24 and 34 days the reaction is somewhat stronger than in adulthood. It can be concluded from these observations that functional maturation of the postganglionic parasympathetic neurones innervating the sinoatrial node in albino rats occurs between the 10th and 20th day of postnatal life.     

Fluorescent probe studies of haptoglobin type 2-1.

Haptoglobin is an alpha2 serum protein that forms an irreversible complex with hemoglobin. The combination between these two macromolecules resembles the binding of an antigen to its antibody except that the complex remains soluble. This investigation was undertaken to determine the nature of the hydrophobic sites on haptoglobin type 2-1. The interaction of 1-anilinonphthalene-8-sulfonate (ANS) with haptoglobin type 2-1 is characterized by a flourescence intensity in solutions containing ANS and haptoglobin as the pH is decreased from 9 to 4. The dissociation constant for the ANS interaction with haptoglobin 2-1 is 5.8 x 10--5 M at pH 7.0, 5.2 X 10--5 M at pH 5.0 AND 30.3 X 10--5 M at pH 4.0. Fmax shows no change in the pH range 6-9 but does show an increase at pH 4.0 when compared to the neutral region.     

Development of diurnal rhythm in some metabolic parameters in foals

1. The development of diurnal rhythm activity of FDPA, AspAT and A1AT and in levels of cortisol, T3 and T4 was observed in the blood serum of six foals. 2. The studies began when a foal was 7 days old and were repeated every month until foals reached 1 year of age. Blood samples were taken every 4 hr for one day each month. 3. As a control group four barren mares were used, kept and examined in the same conditions. 4. In mature mares, diurnal rhythms in activity of A1AT (acrophase at 2200 hr), AspAt (2400 hr) and cortisol (0630 hr) but in T3 only in summer months (acrophase at 0100 hr) were observed. 5. During the first 6 months of foal life, significantly higher mean levels of FDPA, A1AT, T3 and T4 than in control mares were found. 6. The cortisol level in foals was half as much as that of mature mares throughout the year. 7. In foals the diurnal rhythm in A1AT activity occurred in the 5th month and in AspAt--in the 12th month (acrophase at 2400 hr), but in cortisol levels it was developed already in the second month of foal life (acrophase at 0830 hr).     

Corticosterone may interact with peripubertal development to shape adult resistance to social defeat

Studies of social stress in adult mice have revealed two distinct defeat-responsive behavioral phenotypes; “susceptible” and “resistant,” characterized by social avoidance and social interaction, respectively. Typically, these phenotypes are observed at least 1 day after the last defeat in adults, but may extend up to 30 days later. The current study examined the impact of peripubertal social defeat on immediate (1 day) and adult (30 day) social stress phenotypes and neuroendocrine function in male C57BL/6 mice. Initially, peripubertal (P32) mice were resistant to social defeat. When the same mice were tested for social interaction again as adults (P62), two phenotypes emerged; a group of mice were characterized as susceptible evidenced by significantly lower social interaction, whereas the remaining mice exhibited normal social interaction, characteristic of resistance. A repeated analysis of corticosterone revealed that the adult (P62) resistant mice had elevated corticosterone following the social interaction test as juveniles. This was when all mice, regardless of adult phenotype, displayed equivalent levels of social interaction. Peripubertal corticosterone was positively correlated with adult social interaction levels in defeated mice, suggesting early life stress responsiveness impacts adult social behavior. In addition, adult corticotropin-releasing factor (CRF) mRNA in the paraventricular nucleus of the hypothalamus (PVN) was elevated in all defeated mice, but there were no differences in CRF mRNA expression between the phenotypes. Thus, there is a delayed appearance of social stress-responsive phenotypes suggesting that early life stress exposure, combined with the resultant physiological responses, may interact with pubertal development to influence adult social behavior.     

Correlation between plasma growth hormone and insulin and blood glucose concentrations in premature infants.

Plasma growth hormone, insulin and blood glucose levels were measured longitudinally during the first 60 days of life in 21 premature infants (8 males and 13 females) born between the 6th and 8th month of gestation. When these variables were related to age it was found that insulin and glucose, which are lower than in the prepubertal children and adults, rise simultaneously. Whereas growth hormone, which is higher than in older prepubertal children, decreases during the first 2 weeks of life. The decrease in growth hormone continues during the first 2 months of life, in contrast to the increases in insulin and glucose which do not persist in as long a period.     

Premature induction of amylase in pancreas and parotid gland of growing rats by dexamethasone.

Studies were made on changes in the contents of alpha-amylase (EC 3.2.1.1) in the pancreas and parotid gland of rats during postnatal development, on the premature induction of this enzyme by hormones and on the existence of specific glucocorticoid receptors in these tissues. The amylase content in the pancreas increased from the 9th day after birth and reached the adult level on the 28th day, its content in the parotid gland increased rapidly from the 16th to the 28th day after birth and then rose more gradually to the adult level. Injection of dexamethasone into rats 6--8 days after birth induced increase in the amylase of the pancreas but not the parotid gland. However, injection of dexamethasone into weanling rats 21--23 days after birth resulted in precocious induction of amylase in both tissues. Specific glucocorticoid receptors were detectable in the parotid gland of rats from 6 days after birth but were almost undetectable in the pancreas until adolescence.     

Maternal cigarette smoking, metabolic enzyme polymorphism, and developmental events in the early stages of extrauterine life

The recent observation that maternal ACP1 genotype has an interactive effect with smoking on intrauterine development prompted us to search for a possible interaction effect between smoking and ACP1 genotype on haptoglobin (Hp) development in the neonatal period. ACP1 is a highly polymorphic protein tyrosine phosphatase involved in signal transduction of several growth factor receptors. The enzyme is composed of two isoforms, F and S. We studied 299 infants born in the Department of Obstetrics of the University Hospital of Rome La Sapienza. We found that an interaction between ACP1 genotype and smoking has an effect on haptoglobin development: A significant delay of haptoglobin development in infants born to smoking mothers is observed only in infants with the ACP1 *B/*B genotype, which shows the highest concentration of the ACP1 F isoform. The results indicate that the ACP1 genotype modifies the deleterious effects of smoking on development not only during intrauterine life but also during the early stage of extrauterine life.