C16 hydroxylation of 3beta-hydroxy-delta5-steroids during the early neonatal period

Temporal changes of the serum levels of 16-hydroxypregnenolone (3beta,16alpha-dihydroxy-5-pregnen-20-one) 3-sulfate (16-OH-Preg S) and 16-hydroxydehydroepiandrosterone (3beta,16alpha-dihydroxy-5-androsten-17-one) 3-sulfate (16-OH-DHEA S) were investigated by analyzing the levels of their precursor steroids, pregnenolone (3beta-hydroxy-5-pregnen-20-one) 3-sulfate (Preg S) and dehydroepiandrosterone (3beta-hydroxy-5-androsten-17-one) 3-sulfate (DHEA S), respectively, in the early neonatal period. The serum levels of these steroids were measured by GC-MS in full-term (gestational age: 37-41 weeks), pre-term (gestational age: 28-36 weeks) and extremely immature (gestational age: 24-27 weeks) infants. The changes in 16-hydroxysteroid production were also investigated by analyzing the ratios of the serum levels of 16-OH-Preg S and Preg S (16-OH-Preg S/Preg S ratio), and 16-OH-DHEA S and DHEA S (16-OH-DHEA S/DHEA S ratio). It was confirmed that the 16-hydroxylation of DHEA S and Preg S increased after birth, and the 16-OH-Preg S/Preg S ratio in full-term infants was significantly higher than in pre-term and extremely immature infants at days 0, 1-6 and 7-13. On the other hand, there were no significant differences between the 16-OH-DHEA S/DHEA S ratios of the three groups at days 0, 1-6 or 7-13. The mechanism of differences in the 16-hydroxylation of Preg S and DHEA S is also discussed.     

The effect of selenium supplementation during the early post-mating period on embryonic survival in sheep

The functioning of the guinea-pig isolated portal vein was monitored by measuring spontaneous mechanical activity, responses to electrical stimulation and administered noradrenaline in normoxic conditions. The effect of hypoxia, induced by bubbling the physiological bathing solution with a 95% N(2)/5% CO(2) gas mixture, on the mechanical performance of the vein was then assessed. Spontaneous activity declined in hypoxia, with mean contraction tension reduced by 55 + or - 8.8%. The responses to electrical field stimulation (2-32 Hz, 0.7 msec. 70 V) were lowered by 14 + or - 4.6% but contractions produced by a range of noradrenaline concentrations (0.01-160 mu M) were unaffected by hypoxia. Substitution of glucose in the bathing solution with sucrose, a substrate unavailable to the cells for energy generation, produced a marked enhancement of the effect of hypoxia. Spontaneous activity was reduced by 76 + or - 8.3%, electrically-induced activity by 80 + or - 14.4% and noradrenaline-induced responses by 85 + or - 6.8%. Although in normoxia the activity and responses of the portal vein were unaffected by the presence of alpha-tocopherol, it significantly protected the functioning of the vein in hypoxic conditions. This effect was concentration-dependent within the range 10-160 mu M and was most marked when glucose was replaced by sucrose in the bathing solution.     

Controlling factors in the development of ceruloplasmin in pigs during the neonatal growth period

The sequence of ceruloplasmin development and limiting factors controlling this process in neonatal piglets was studied in a randomized block design. Guided by the change in serum ceruloplasmin levels, the liver copper concentrations of piglets fed copper-deficient and copper-supplemented diets were compared in three different periods. The plasma of piglets was devoid of both apo- and holo-ceruloplasmin at birth. The system responsible for the synthesis of apoceruloplasmin developed shortly after birth as indicated by a steady increase in serum ceruloplasmin activity during the first week without being affected by the diet. Copper apparently was not the limiting factor at this stage since very high concentrations of copper were found in the livers of newborn piglets. However, the liver copper was depleted quickly within 1 to 2 weeks and became the limiting factor if the diet was deficient in copper. The livers of these piglets were fractionated by differential centrifugation to compare the liver copper distribution in the two dietary groups with and without copper supplementation. The treatments did not affect the copper distribution on a percentage of total liver copper basis. However, fractionation study revealed that, unlike adult pig livers, about 70% to 80% of copper was present in the heavier particle fractions of piglet livers.     

Congenital malformations presenting during the neonatal period

Discharge of the newborn within 24 to 48 hours after birth makes it more difficult to detect some congenital malformations and increases the need for careful examination and review of the history of the pregnancy, delivery, and nursery course. Progressive physiologic changes after birth, especially in the cardiovascular system, precede the development of signs indicative of disease for certain congenital malformations. Discharge before these changes occur may delay their detection because the newborn is not being monitored by medical or nursing caregivers. The AAP Committee on the Fetus and Newborn has published guidelines for criteria for safe discharge and follow-up evaluation to help create a safe situation for such early discharges. Some specific observations at birth may lead to earlier diagnosis. Careful attention to subtle differences between the initial and follow-up examination, such as a changing cardiac murmur or quality of pulses or abdominal fullness, may provide clues to the diagnosis of congenital malformations. Coordinated suck and swallow with successful feeding and passage of stool and urine within 24 hours after birth should occur before discharge. Reports of feeding difficulties should be reviewed. Although a thorough examination is facilitated by a sleeping infant, documentation of a normal pitched cry helps in the evaluation of the upper airway. Parents should be counseled about signs of illness that warrant medical attention, and early follow-up is needed to detect problems early enough to intervene effectively. In addition, although passage of a feeding tube through each nare and to the stomach with aspiration and measurement of gastric volume is not a routine procedure in the well, term newborn, this may be a useful early diagnostic tool in infants with signs or a maternal or nursery history suggestive of nasal or GI obstruction.     

Alterations in the developmental properties of stroma during the development of the urogenital ridge into ductus deferens and uterus in embryonic and neonatal mice

The ability of mesenchyme from the urogenital ridge to participate in the development of male and female urogenital organs was studied by preparing homo- and heterotypic recombinants of epithelium and stroma from ductus deferens and uterus of neonatal mice. The recombinants as well as intact 14-day old embryonic urogenital ridges (URG) were grown for two to eight weeks in adult male and female hosts. The development of ductus deferens and seminal vesicle from female UGR's grafted into male hosts and uterus from male UGR's grafted into female hosts demonstrate that the mesenchyme of embryonic UGR's is capable of participating in the development of either male or female urogenital structures. During normal development of the female urogenital tract, the bisexual morphogenetic potentiality of UGR mesenchyme persists postnatally as demonstrated by the ability of uterine stroma to support normal differentiation of epithelium of ductus deferens in male hosts. Conversely, during the normal development of the male urogenital tract, the morphogenetic potentiality of mesenchyme of the urogenital ridge is restricted as stroma from the ductus deferens appears incapable of participating in uterine morphogenesis in male or female hosts. These differences in the developmental properties of UGR stroma may be attributed to differences in hormonal conditions in male and female fetuses.     

Doppler ultrasound of blood flow velocities in ophthalmic and central retinal arteries during the early neonatal period

Dopamine has been implicated as a potential mediating factor in a variety of neurodegenerative disorders. Dopamine can be oxidized to form a reactive dopamine quinone that can covalently modify cellular macromolecules including protein and DNA. This oxidation can be enhanced through various enzymes including tyrosinase and/or prostaglandin H synthase. One of the potential targets in brain for dopamine quinone damage is tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis. The present studies demonstrated that dopamine quinone, the formation of which was enhanced through the activity of the melanin biosynthetic enzyme, tyrosinase, covalently modified and inactivated tyrosine hydroxylase. Dihydroxyphenylalanine (DOPA; the catechol-containing precursor of dopamine) also inactivated tyrosine hydroxylase under these conditions. Catecholamine-mediated inactivation occurred with both purified tyrosine hydroxylase as well as enzyme present in crude pheochromocytoma homogenates. Inactivation was associated with covalent incorporation of radiolabelled dopamine into the enzyme as assessed by immunoprecipitation, size exclusion chromatography, and denaturing sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis. Furthermore, the covalent modification and inactivation of tyrosine hydroxylase was blocked by antioxidant compounds (dithiothreitol, reduced glutathione, or NADH). In addition to kinetic feedback inhibition and the formation of an inhibitory dopamine/Fe+3 complex, these findings suggest that a third mechanism exists by which dopamine (or DOPA) can inhibit tyrosine hydroxylase, adding further complexity to the regulation of catecholamine biosynthesis.     

Fertilization and early embryonic development in poultry

There are two major controllers of development in the early stages of bird embryos. These are: 1) gravity, probably acting through the distribution of yolk and its components, which lays down the initial plans for polarity that are later established firmly through the genes; and 2) the primitive streak, which controls the orderly ingression of the cells and imposes a pattern on the developing tissues.     

Vitamin and mineral transfer during fetal development and the early postnatal period in pigs

There are periods during pregnancy when sows may have a temporally high requirement for certain vitamins and minerals. Proteins transferring retinol and Fe to the developing pig fetus have been discovered, whereas transport mechanisms for other vitamins and minerals are probably present but have not yet been identified. Sow body tissues can serve as a reservoir for many micronutrients, but it is not known whether these reserves can supply an adequate quantity during critical fetal developmental periods. There is a low placental transfer of vitamin E to the fetus even if the dietary concentration fed to a gestating animal is high, but colostrum and milk concentrations can be increased when the nutrient is fed to sows. If the dam's diet contains inadequate Ca or P, the concentration of these elements in the developing fetus and milk will not be affected. Consequently, sow bone demineralization will occur under conditions of dietary inadequacy of Ca and P. Other nutrients can be depleted from sow tissue reservoirs over several parities (e.g., Se), resulting in low quantities being provided in the milk for nursing pigs. Scientific information involving adequate vitamin and mineral nutrition for female pigs to improve conception rate and embryonal survival that will result in optimum fetal and postnatal pig development can be considered to be in its infancy.     

Massive loss of mid- and hindbrain neurons during embryonic development of homozygous lurcher mice

The mouse neurological mutant lurcher (Lc) results from a semidominant mutation. Heterozygous Lc/+ mice are viable but ataxic because Lc/+ Purkinje cells die by apoptosis within the first 3 weeks of life. Lc/Lc mice die shortly after birth. To aid in understanding the function of the lurcher gene product, we have examined the embryonic development of homozygous lurcher animals. The ratio of +/+:Lc/+:Lc/Lc animals did not deviate significantly from the expected 1:2:1. Homozygous lurcher mice at P0 were found to be normal under gross morphological examination. However, these mice weighed less, lacked milk in their stomach, and died within the first day of life. No resorbed embryos were found at embryonic day (E) 17.5, indicating that all homozygous lurchers survived until birth. Histological examination of P0 animals revealed that in homozygous lurcher mice the patterning of the brain is normal but that there has been a massive loss of hindbrain neurons during embryonic development. A particularly conspicuous consequence of the Lc/Lc genotype at birth is the complete absence of large neurons comprising the trigeminal motor nucleus. These neurons arise normally and are maintained until E15.5. However, beginning at E15.5 large numbers of pyknotic cells are evident in the trigeminal motor nucleus, suggesting that these cells die coincident with their terminal differentiation in the developing hindbrain. Because the trigeminal motor nucleus controls muscles required for suckling, these results suggest an explanation for the neonatal death of homozygous Lc animals. These data demonstrate that the severe and dose-dependent developmental consequences of lurcher gene action result from degeneration of distinct neuronal populations on maturation in the developing CNS.     

Serum thyrotropin, prolactin, and growth hormone levels during the early neonatal period in the human infant

The purpose of this study was to evaluate the efficacy of a trapezoidal wave form for ventricular difibrillation. Overall efficacy showed the trapezoidal waveform to be effective for defibrillation, including patients weighing over 100 kg (220 lb). We concluded that (1) the trapezoidal waveform is an effective defibrillatory pulse and (2) the trapezoidal waveform offers pulse characteristics less deleterious than other established waveforms.     

Inhalation of an extract from the leaf buds of the deltoid poplar during the early period following tonsillectomy

To prevent inflammatory processes in the mucous membrane of the upper respiratory tract during early periods after tonsillectomy (2-7 days) the authors practiced inhalations of the extract of Eastern poplar leaf buds in 40 patients with chronic tonsillitis after the operation. The use of the extract of Eastern poplar leaf buds at early periods after tonsillectomy promotes abating of pains, speedy cicatrization of postoperative wounds, decrease of reactive inflammation in the pharynx and improvement of the general condition in the patients.     

Calpain localization changes in coordination with actin-related cytoskeletal changes during early embryonic development of Drosophila

Calpain, a calcium-dependent intracellular protease, was identified in Drosophila melanogaster. Drosophila calpain has an amino acid sequence highly homologous to those of mammalian calpains and exhibits a distinct domain structure consisting of cysteine protease and calcium-binding domains. Specific antibodies raised against a recombinant calpain fragment were used to identify the localization of calpain in developing Drosophila embryos. Calpain was first detected near the anterior pole and in posterior region of the embryo just after fertilization. The anterior calpain disappeared during the cleavage cycles. On the other hand, the posterior calpain moved to the posterior pole when polar buds were formed, and condensed just below the pole cells. At cleavage cycles 8 and 9, when nuclei reached the egg surface, calpain was localized between the nuclei at the surface beneath the precleavage furrows. Co-staining experiments with anti-actin antibody revealed that calpain condenses specifically at the edge of and between actin caps that underlie the plasma membrane immediately above each nucleus. These results indicate that calpain is involved in the dynamic changes in the embryonic cytoskeleton, especially actin-related structures, during early embryogenesis prior to cellularization.     

Expression of mouse c-myb during embryonic development

Three members of the myb gene family, designated as A-myb, B-myb, and c-myb, have been described in many vertebrates. A large body of evidence indicates that the c-myb gene is essential for the development of most hematopoietic lineages. By contrast, the functions of A-myb and B-myb are less well understood. To further explore the relationship between the different myb family members we have compared the expression of A-myb and c-myb during mouse embryogenesis by Northern blotting and by in situ hybridization. In accordance with the important role of c-myb in the hematopoietic system, we detect high levels of c-myb expression in hematopoietic organs such as the fetal liver and the thymus. Surprisingly, we find that high levels of c-myb expression are not restricted to hematopoietic cells. We show that c-myb is strongly expressed in the neural retina and in epithelia of the respiratory tract. The side-by side analysis of c-myb and A-myb expression clearly shows that both genes are expressed in different, but overlapping sets of tissues. Our results suggest that the function of c-myb may not be restricted to hematopoietic cells.     

The value of endoscopic treatment for ureteroceles during the neonatal period

PURPOSE: We report a series of 35 neonates presenting with ureterocele diagnosed during the antenatal period or during the first weeks of life. The first line treatment was an endoscopic incision. MATERIALS AND METHODS: Immediate postnatal evaluations detected 37 ureteroceles (bilateral in 2 cases), including 16 of the intravesical type and 21 that were ectopic. Endoscopic incision permitted decompression of the majority of ureteroceles and improvement in renal function in most cases. Secondary low grade vesicoureteral reflux appeared in 9 neonates (ectopic in 8 cases) and had already been present in 14 patients. RESULTS: Endoscopic treatment alone proved effective in 14 of the intravesical ureteroceles, while the other 2 cases requiring upper pole nephrectomy (1) and ureterovesical reimplantation using the Cohen technique (1). In contrast, among patients with the ectopic form additional surgery was necessary in 18 cases. Treatment comprised resection of the ureterocele with bladder reconstruction and ureteral reimplantation without remodeling according to the Cohen technique in 15 cases, total ureteronephrectomy in 1 and pole nephrectomy in 2. CONCLUSIONS: We suggest that early endoscopic incision be used for first line treatment of ureteroceles. The aim of this procedure is to ensure better urine drainage, preserve function of the parenchyma and reduce the risk of severe infection in the neonate. The principal complication remains secondary vesicoureteral reflux onset, which can be controlled well by antibiotic prophylaxis but requires regular radiological monitoring.     

Identification of the blood-borne somatotroph-differentiating factor during chicken embryonic development

Somatotrophs become a significant population by day 16 of chicken embryonic development. We have previously demonstrated that an earlier induction of GH cell differentiation is possible with the addition of day 16 embryonic serum to cultures of day 12 pituitary cells, an age when somatotrophs are rare. The present study was designed to identify the blood-borne signal(s) responsible for the serum activity, using reverse hemolytic plaque assays to identify individual GH-secreting cells. The activity was found to be a heat-stable, ether-soluble compound(s) that is bound or inhibited by a trypsin-sensitive protein. The extent of GH cell differentiation was greater (P < 0.05; n = 3) in response to the ether phases of heated day 16 (14.1 +/- 0.4% of all cells) and day 12 sera (9.3 +/- 0.4%) than with untreated serum from days 16 and 12 (6.1 +/- 0.4% and 0.82 +/- 0.4%, respectively). Furthermore, ether-extracted day 16 serum was more effective than ether-extracted day 12 serum, which was also different from basal (0.85 +/- 0.4%; P < 0.05). Based on this biochemical profile, the abilities of various steroids to stimulate differentiation were tested. Three steroids were found to stimulate somatotroph differentiation in vitro: 17beta-estradiol, corticosterone, and progesterone. However, the estradiol receptor antagonist, tamoxifen, while abolishing the effect of estradiol, had no effect on the induction of differentiation by day 16 serum. In contrast, RU486, a specific glucocorticoid receptor antagonist in chickens, blocked the stimulatory effects of corticosterone, progesterone, and day 16 serum on somatotroph differentiation. We next tested whether the active compound in day 16 embryonic serum was corticosterone, the predominant glucocorticoid in chickens. Incubation of day 16 serum with corticosterone antiserum, but not control antiserum, suppressed day 16 serum-induced GH cell differentiation. Therefore, we conclude that corticosterone is the blood-borne signal capable of stimulating somatotroph differentiation in vitro. The present findings together with previous reports indicate that somatotroph differentiation during embryonic development may result from an increase in circulating glucocorticoid concentrations.     

Functioning of the porcine pituitary-adrenocortical axis during neonatal development

A study was conducted with neonatal boars to measure age-related changes in functioning of the pituitary-adrenocortical axis. Pigs were randomly assigned to control (n = 7-10/age) or treated (1-min restraint, n = 9-11/age) groups to be sampled at either 12, 19, or 26 days of age. Blood samples were taken via catheter 10 min before and 3, 10, and 20 min after restraint or at similar time intervals in controls. One day later, pigs were killed and adrenal glands obtained for ACTH receptor measurements. Basal plasma ACTH concentrations were greatest (p = 0.035) on day 12 when compared with later ages, but basal plasma cortisol concentrations were comparable at the three ages. Compared with controls, restraint elevated incremental plasma ACTH and cortisol responses at each age (p < 0.004). On day 12, maximal plasma ACTH (p = 0.0006) and incremental cortisol (p < 0.006) responses to restraint were greater than at later ages. Binding to adrenal ACTH receptors was greatest (p < 0.05) at day 13, which may help explain the apparently increased in vivo response of the adrenal gland to ACTH at this time. Restrained pigs had increased growth rates with increasing age (p = 0.016) whereas growth rates for control pigs did not differ with age. At day 27, 24 h after the 1-min restraint, body weights of restrained pigs exceeded those of control pigs (p = 0.045). At day 20, adrenal DNA and protein in pigs restrained 24 h previously were greater than in control pigs (p < 0.05). These data suggest age-related changes in functioning of the pituitary-adrenal axis in neonatal boars, and an absence of period during neonatal life when the porcine pituitary adrenocortical axis cannot respond to a stressor. The data also indicate both rapid and long-term responses of the adrenal to a very modest stressor and suggest an extreme sensitivity of neonatal pigs to environmental perturbations.