Showing papers on "Fetus published in 1968"
TL;DR: This paper presents a practical method for applying clinically the principles described by these authors, and concludes that brain development during fetal life progresses independently of unfavourable gestational circumstances.
Abstract: Cerebral maturation during the last three months of fetal life brings about constant modification of muscle tone and of certain reflexes. This has enabled a scheme to be devised, whereby the neurological maturity of the premature infant at different ages can be assessed. Saint-Anne Dargassies (1955) defined this neurological progression by analysing a group of 100 prematures of known gestational age, and the longitudinal evolution of healthy prematures, born at 28 weeks' gestational age and studied up to 40 weeks' gestational age. The clinical results have been compared with the electroencephalographic (Dreyfus-Brisac, Flescher, and Plassart, 1962) and anatomical (Larroche, 1962) stages of development of the brain. In applying this maturation scheme to 'small-for-dates' babies it has been concluded that brain development during fetal life progresses independently of unfavourable gestational circumstances. Chronic fetal stress is reflected mainly in the birthweight and to a lesser degree in the body length at birth. The brain, however, from the point of view of anatomy and physiology, evolves more in proportion to the gestational age (Gesell and Amatruda, 1945; Bergstrom, Gunther, Olow, and Soderling, 1955; Saint-Anne Dargassies, 1955). The original observations on which this paper is based are those of Minkowski, Larroche, Vignaud, Dreyfus-Brisac, and Saint-Anne Dargassies (1966). This paper presents a practical method for applying clinically the principles described by these authors. Butler and Bonham (1963) estimated that a third of infants weighing less than 2500 g. have a gestational age greater than 38 weeks. The small-for-dates baby is liable to develop serious metabolic disturbance shortly after birth; for this reason it is imperative that the assessment of gestational age be made early. Occasionally the initial neurological evaluation of maturation is confused by signs of neurological disorders. But, as a rule, neurological examination during the first days of life can provide
302 citations
TL;DR: A method of estimating the magnitude and distribution of umbilical blood flow by means of radioactive microspheres in sheep fetuses in utero and the steady-state diffusion technique showed agreement within ±11%.
Abstract: A method of estimating the magnitude and distribution of umbilical blood flow by means of radioactive microspheres in sheep fetuses in utero is described. Simultaneous measurements of total umbilical flow by this method and the steady-state diffusion technique showed agreement within ±11%. In 11 fetuses of 90 to 150 days gestational age, the distribution of umbilical flow to the intercotyledonary chorion was 6.2±0.8% of the total. This information has been used to estimate the effect of venous admixture of cotyledonary and noncotyledonary blood on the umbilical vein-uterine vein concentration difference of inert molecules with flow-limited transplacental clearance.
222 citations
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TL;DR: In this paper, a tentative timetable for man is presented which correlates specific types of abnormalities with irradiation during particular stages of gestation when the dose is in the range of therapeutic irradiation.
Abstract: Severe and obvious abnormalities encountered in 26 children who received heavy x-radiation during various stages of gestation were compiled and evaluated. The following conditions occurred most frequently: stunted growth, microcephaly, mental retardation, microphthalmus, pigmentary degeneration of the retina, cataracts, genital and skeletal anomalies. A tentative timetable for man is presented which correlates specific types of abnormalities with irradiation during particular stages of gestation when the dose is in the range of therapeutic irradiation. On the basis of the patient material presently available and with some support of experimental data the following generalizations are made: (1) Moderately large dose of ionizing radiation (over 250 R but the upper limit cannot be stated) delivered to the human embryo before 2–3 weeks of gestation is not very likely to produce severe abnormality in most of the children born although experimental data indicate that considerable numbers of these embryos are resorbed or aborted (23,24). (2) Irradiation of the fetus with doses used in medical therapeutics between 4 and 11 weeks of gestation would lead to severe abnormalities (predominantly malformation) of many organs in most or all of the children. (3) Irradiation in a similar dose range between 11 and 16 weeks of gestation may produce little or no eye (late cataracts not considered), skeletal and genital organ abnormalities but stunted growth, microcephaly and mental retardation is frequently present. (4) Irradiation of the fetus between 16 and 20 weeks of gestation with a similar dose range may lead only to mild degrees of microcephaly, mental retardation and stunting of growth. (5) Irradiation of the fetus with a similar dose range after 20 weeks of gestation is not likely to produce overt abnormalities leading to a serious handicap in early life. However, a proportion of the infants may show evidence of irradiation exposure such as skin erythema, abnormal pigmentation, epilation, or deficiencies in the hematopoietic system.
150 citations
TL;DR: It is proposed that bradykinin is produced at birth and may be a mediator of neonatal circulatory changes and the role of kinins as mediators of such changes.
Abstract: Bradykinin is a potent constrictor of the human umbilical artery and vein and the ductus arteriosus of the lamb in vitro at oxygen tensions above 40 mm Hg (comparable to those in the newborn infant). Bradykinin is also capable of producing remarkable dilatation of the pulmonary vasculature of the lamb. Theoretically, kinins are capable of effecting some of the rapid circulatory changes required of the neonate. The present study was undertaken to investigate the role of kinins as mediators of such changes. The concentration of bradykinin in the cord blood of 56 newborn infants at the time of birth was significantly higher than the blood level in adult subjects (12.8 +/- 4.3 ng/ml compared with 2.0 ng/ml or less). Cord arterial blood contained inactive kinin precursor (kininogen) and inactive kinin-releasing enzyme (kallikrein). Plasma kallikrein was activated, with subsequent kinin formation and kininogen depletion, by exposure to neonatal granulocytes or by a decrease in the temperature of cord blood from 37 to 27 degrees C. A comparable decrease in the temperature of umbilical arterial blood occurs at the time of birth. Activation of kallikrein by neonatal granulocytes was dependent on cell concentration and required oxygen tensions comparable to those in the neonate but above the range in the fetus. Granulocytes of the neonate, unlike those of adult subjects, lacked kininase activity.Thus, bradykinin can constrict and dilate vessels as required for the transition of fetal to neonatal circulation. Bradykinin can be produced in plasma of the newborn by decreases in temperature, such as occur in the umbilical blood at birth, and by exposure to granulocytes which are present in the circulation in increased numbers shortly after birth. We propose that bradykinin is produced at birth and may be a mediator of neonatal circulatory changes.
121 citations
TL;DR: Perfusion of guinea pig placenta in situ, following removal of the fetus, demonstrated the primary role of the placente in establishing a concentration gradient toward the fetus and it was demonstrated that the amino acid was transferred across the Placental transport in both directions, apparently more rapidly towards the fetus than in the reverse direction.
118 citations
TL;DR: The finding in this study indicate that cell division in the human brain appears to continue until five months of age ceases thereafter and that further growth occurs by increase in protein, RNA and, perhaps, lipid content of cells.
Abstract: Extract: In order to establish the pattern of cellular growth, nucleic acid and protein content were serially determined in 31 human brains The eraliest-material was obtained from a fetus with a gestational age of 13 weeks; the latest from a 13-month-old infant Weight, protein, and RNA content increased linearly during this period Weight increased from 5 g to 970 g, protein from 193 mg to 53 g, and RNA from 185 to 1384 mg In contrast, increase in DNA content began to level off at about the time of birth and reached a maximum (approximately 900 mg) by five months of age These data indicate that very little cell division occurs in the human brain after five months of age and that further growth occurs by increase in protein, RNA and, perhaps, lipid content of cells
113 citations
TL;DR: Hyperbaric oxygenation seems to establish a circulatory pattern in the fetus similar to that of the early neonatal period, and indicates that the fetal pulmonary vascular bed is sensitive to oxygen in that it undergoes vasodilatation when the oxygen tension of the blood passing through it rises; the ductus arteriosus responds to the same stimulus by constricting.
Abstract: The effects of hyperbaric oxygen (at 3 atmospheres absolute) on uteroplacental and fetal circulations were studied in pregnant ewes near term. The ewe was given spinal anesthesia, the fetus was marsupialized to the abdominal walls to protect the umbilical circulation, and the fetal head was covered with a saline-filled glove to prevent breathing. During hyperbaric oxygenation, maternal arterial blood Po 2 rose to 1,300 mm Hg while umbilical vein blood Po 2 rose to 300 mm Hg; umbilical arterial Po 2 rose to only 50 mm Hg. Maternal and fetal arterial pressures did not change significantly, but uteroplacental and umbilical flows decreased slightly. Ductus arteriosus blood flows decreased strikingly when the oxygen tension of the pulmonary blood rose; net pulmonary blood flow increased markedly because of a decrease in pulmonary vascular resistance produced by oxygen. Ascending aortic flow increased, but effective fetal cardiac output (aortic plus ductus arteriosus flows) decreased. These studies indicate that the fetal pulmonary vascular bed is sensitive to oxygen in that it undergoes vasodilatation when the oxygen tension of the blood passing through it rises; the ductus arteriosus responds to the same stimulus by constricting. Hyperbaric oxygenation seems to establish a circulatory pattern in the fetus similar to that of the early neonatal period.
103 citations
TL;DR: Fetal mice of the C57BL/6J strain used in a study of the rates of synthesis of RNA, total protein and hemoglobin by developing erythroid cells derived from two different sites of erythropoiesis are suggested to be limited by a relatively short-lived component essential to protein synthesis, which may be messenger RNA.
103 citations
TL;DR: These studies confirm the previous findings that the first fraction obtained from the Sephadex of lung extracts contains the lung surfactant system and that lung Surfactant is not lipoprotein.
68 citations
TL;DR: Determinations of levels of a local anesthetic during labor after paracervical block indicated a rapid absorption of the drug into the maternal blood, with peak concentrations achieved by 10 to 20 minutes, followed by prompt placental passage to the fetus.
Abstract: Determinations of levels of a local anesthetic (mepivacaine) during labor after paracervical block indicated a rapid absorption of the drug into the maternal blood, with peak concentrations achieved by 10 to 20 minutes, followed by prompt placental passage to the fetus. The fetal bradycardia frequently encountered with this form of anesthesia appears to be related to high concentrations of the drug in fetal blood, 12.8 to 15 μg per milliliter. Although such levels might cause neonatal depression they do not appear to be high enough to cause death of a healthy fetus. Fetal bradycardia as a result of drug toxicity should be distinguished from that due to fetal asphyxia. Paracervical block is contraindicated when placental insufficiency is anticipated.
62 citations
TL;DR: The preferential utilization of glucose for the synthesis of fetal brain cholesterol emphasizes the significance of the "blood-brain barrier" which controls the movement of substances into and out of central nervous system tissue.
TL;DR: There appeared also to be no sexual or age differences in the ability of the implants to secrete gonadotropin, at least for the hypophyses of fetuses between 11 and 28 weeks of embryogenesis.
TL;DR: The data suggest that although fetal serum contains significant concentrations of insulin derived from fetal (β-cells, the exact metabolic role of this insulin in the fetus is unclear.
Abstract: Serum IRI (immunoreactive insulin) in twenty-day fetuses from mothers fed ad libitum exceeded maternal levels. Increasing maternal IRI produced by injection of exogenous insulin or by intravenous glucose loading did not produce significant changes in fetal IRI. The twenty-day pregnant rat in the basal state distributed relatively more C-14 from radio glucose into lipid and glycogen and relatively less into protein than a nonpregnant control under similar conditions. Incorporation of C-14 from radioglucose was augmented by exogenous insulin at fifteen minutes into lipid in maternal liver and adipose tissue, protein into liver and glycogen in muscle. Neither the incorporation of C-14 into lipid, glycogen, or protein from radioglucose nor the incorporation of H3 (from H32O) into fatty acids was influenced by exogenous insulin in the fetus. This was true even when the insulin was injected directly into the fetus. On the other hand, fetal incorporation of radioglucose into glycogen was augmented significantly by an acute glucose load. The data suggest that although fetal serum contains significant concentrations of insulin derived from fetal (β-cells, the exact metabolic role of this insulin in the fetus is unclear.
TL;DR: The accumulation of adrenergic nerves and smooth muscle cells in the wall at the origin of the ductus venosus supports the theory of an adrenergic sphincler mechanism at this by-pass.
Abstract: Ehinger, B., G. Gennser, Ch. Owman, H. Persson and N.-O. Sjoberg. Histochemical and pharmacological studies on amine mechanisms in the umbilical cord, umbilical vein, and ductus venosus of the human fetus. Acta physiol. scand. 1968. 72. 15–24.
The response in vitro of the umbilical vein and the ductus venosus to certain pharmacologically active drugs hls been correlated with the adrenergic and cholinergic innervation of this venous system in human fetuses of 20–24 weeks gestational age. No histochemically demonstrable adrenergic or cholinergic nerves occurred in the umbilical cord. In the intra-abdominal part of the umbilical vein an increasing amount of adrenergic nerves were present in direction towards the ductus venosus. A distinct accumulation of adrenergic nerves was observed at the origin of the ductus venosus, concomitant with an increased thickness of the smooth muscle wall of the vessel. Few, if any, acetylcholinesterase-containing fibres could be demonstrated in relation to the umbilical vein or ductus venosus. Noradrenaline, acetylcholine, and 5-hydroxy-tryptamine produced a contractile response in the intra-abdominal portion of the umbilical vein as well as ir the first part of the ductus venosus. The noradrenaline response could be reproduced by tyramine and abolished by phenoxybenzamine, which potentiated the contraction induced by 5-hydroxytryptamine. Atropine inhibited the effect of acetylcholine, but not that of noradrenaline. The presence of aminergic nerves is not indispensable for the existence of vascular smooth muscle receptors for the amines. The accumulation of adrenergic nerves and smooth muscle cells in the wall at the origin of the ductus venosus supports the theory of an adrenergic sphincler mechanism at this by-pass.
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TL;DR: In this paper, the effects of single umbilical artery ligation have been studied in 20 lamb fetuses, using chronic indwelling catheters placed in a retrograde fashion via the ligated cord in the fetal aorta.
Abstract: The effects of single umbilical artery ligation have been studied in 20 lamb fetuses, using chronic indwelling catheters placed in a retrograde fashion via the ligated umbilical artery in the fetal aorta. Fetal arterial blood pressure, heart rate, blood pH, PCO 2 and PO 2 were monitored at various intervals until the end of the gestation. The results indicate that prolonged fetal survival is possible. Although fetuses near term did not survive this insult, long-term survival (3 to 56 days) was observed in nine animals of earlier gestational age. After an initial period of hypoxia, acidosis, and hypercapnia, stabilization occurred and "normal" values for these parameters were observed. In spite of the apparently normal gas and hydrogen exchange between mother and fetus, profound fetal malnutrition was observed in two animals who survived 26 and 56 days, respectively. The possible mechanisms of fetal adaptation to this acute change in intra-uterine environment and the potential value of this "experimental model" for studying chronic fetal distress due to placental insufficiency are discussed.
TL;DR: The persistence of radioactivity in fetal and maternal tissues for 1 week after injection indicated that prolonged binding of the isotope must also occur in tissues, and the possibility of a direct teratogenic action of tellurium on the fetus was considered.
TL;DR: It appears clearly that thyroid hormones play a role in the development of mammals during both the prenatal and the postnatal period; the nature and the intensity of their effect vary according to the developmental stage.
TL;DR: Comparison of renin activities in umbilical venous and arterial plasma demonstrated that the fetus (presumably the fetal kidneys) can produce renin and that the placenta is capable of adding or removing renin from the fetal blood.
Abstract: Plasma renin activity was consistently elevated during the third trimester of pregnancy. The renin levels during labor were significantly elevated when compared to the third trimester values for the same women. No significant change occurred during parturition or for the first week post partum, indicating that neither the placenta nor fetus was the source of the elevated maternal plasma renin. By 6 weeks post partum, plasma renin had returned to normal. Comparison of renin activities in umbilical venous and arterial plasma demonstrated that the fetus (presumably the fetal kidneys) can produce renin and that the placenta is capable of adding or removing renin from the fetal blood.
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TL;DR: The results indicate that lymphoid stem cells which have the potential to participate in cell-bound immune reactions appear in the placenta and liver by the 9th or 10th day of gestation, and throughout pregnancy they are found in the liver.
Abstract: Summary The presence of potential immunologically competent cells in the various tissues of embryonic, newborn and adult mice was demonstrated by means of a modified γgraft- vs. -host” method and by the injection of chromosomally marked cells into irradiated recipients. The results indicate that lymphoid stem cells which have the potential to participate in cell-bound immune reactions appear in the placenta and liver by the 9th or 10th day of gestation. Throughout pregnancy they are found in the liver. During the 11th to 14th days of gestation these stem cells are present in the upper trunk or in the thymus. On about the 15th day they appear in the lung and toward the end of the pregnancy in the fetal bone marrow and spleen. There was little or no evidence of the presence of lymphoid precursors capable of maturation to cells which mediate cell-bound immune responses in the gut prior to birth. Following parturition lymphoid stem cells were present in the liver, Peyer9s patches, lung, bone marrow, lymph nodes, spleen, blood and thymus. However, by 6 weeks after birth the bone marrow appeared to be the major or sole source of these cells.
TL;DR: In cases of hypertensive disorder there is an increase of urea in the cord vein plasma and the increase seems to be secondary to an occasional increase in the maternal plasma.
Abstract: Summary
In cases of hypertensive disorder there is an increase of urea in the cord vein plasma. The increase seems to be secondary to an occasional increase in the maternal plasma.
In cases of hypertensive disorder during pregnancy associated with intrauterine growth retardation of the foetus the ratio between the cord vein plasma levels and the mother's cubital vein plasma levels of essential amino acids is lower than under normal conditions. The low ratios of valine, isoleucine and leucine levels are shown to be due to higher maternal plasma levels at delivery than in normal pregnancies. It is suggested that the findings have some bearing on the growth retardation of the foetus, being the consequence of a diminished supply of essential amino acids to the foetus.
The differences from what is found in normal term pregnancies are not due to a shortening of the gestational period, since there is in the foetus, in a gestational period down to 33 weeks, only still higher plasma levels of taurine and lysine.
To demonstrate that the material is representative as regards hypertension and the “small-for-dates” syndrome a survey has been made of the weight and length at birth in cases of hypertensive disorder during pregnancy.
TL;DR: The presence of 6β-hydroxylase activity in the fetal liver microsomes indicates that the Fetal liver — as well as the placenta — is able to form 6 β-hydroxy-C19-steroids, a precursor of the 6-Hydroxylated estrogens found in human pregnancy urine.
TL;DR: The carbon dioxide tension decreases significantly during the observed period in all four vessels, suggesting an increasing hyperventilation of the mother towards the end of pregnancy.
TL;DR: Although cord blood studies at delivery gave no evidence of intrauterine asphyxia, the presence of chronically limited oxygen supply is suggested by an elevation of hemoglobin concentration in cord blood and the low weight for gestational age of infants at birth.
TL;DR: Pregnancy can be diagnosed in sheep and pigs from 9 weeks and 7 1 2 weeks respectively by a portable ultrasonic instrument (“Doptone”) which amplifies reflected ultrasonic signals.
TL;DR: In rats, the influence of pregnancy, fetuses, fetal placentas and pseudopregnancy with and without deciduomas on mammary and uterine development (DNA content) and metabolism (RNA content) was studied and it is suggested that maternal hormones are the primary stimulant of mammary development during the first half of pregnancy.
Abstract: In rats, the influence of pregnancy, fetuses, fetal placentas and pseudopregnancy with and without deciduomas on mammary and uterine development (DNA content) and metabolism (RNA content) was studied. Mammary nucleic acid content increased throughout pregnancy. Removal of fetuses before midpregnancy, but not after, interfered with normal increases in mammary DNA and RNA content. Excision of fetal placentas caused mammary development to regress to nonpregnant control values. Mammary development during the first 12 days of pseudopregnancy was 29–33% less than that observed in 12-day pregnant rats. It is suggested that maternal hormones are the primary stimulant of mammary development during the first half of pregnancy. However, the fetal placentas commence to stimulate mammary development before midpregnancy, and they may be the primary limiting factor for mammary development during the second half of pregnancy. Uterine DNA increased 2.8-fold, whereas uterine RNA and weight increased 5.8- and 4.6-fold, resp...
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