Quantitative influence of non-hormonal blood factors on the control of sodium excretion by the isolated dog kidney

Quantitative influence of non-hormonal blood factors on the control of sodium excretion by the isolated dog kidney.On the basis of experiments performed on isolated dog kidneys, thus eliminating extrarenal hormonal controls, an attempt has been made to evaluate the influence of arterial blood pressure and several non-hormonal blood parameters on fractional sodium excretion.The roles of plasma protein concentration as modulated by filtration fraction, total renal plasma flow, hematocrit, arterial pressure and plasma potassium concentration on overall fractional sodium reabsorption have been evidenced and quantitatively evaluated.Although the control of sodium reabsorption by renal plasma flow and by hematocrit can be ascribed partly to changes in filtration fraction and post-glomerular plasma protein concentration, other mechanisms appear to be involved as well.Variations in filtration fraction and postglomerular plasma protein concentration play little, if any, role in the induction of pressure natriuresis.The autonomous and quantitative response of the kidney to blood dilution during saline diuresis represents the cumulative results, not only of the dilution of pre- and postglomerular plasma proteins, but also of the simultaneous decrease of hematocrit and increase of renal plasma flow.The implications of these results for the understanding of the adjustment of sodium balance in acute and chronic conditions are discussed

To Give Birth: In the Past and Today

Nowadays in industrialized regions, the majority of childbirths take place in a hospital under high medical and paramedical supervision; this renders the rate of perinatal events very low. This obstetrical safety progressively developped through a practice that, at times, was studded with strange recommendations as well as ingenious concepts. The progress of Medicine and the emancipation of Woman deeply modified the approach to child delivery and influence the importance of its different actors. The current tendency towards a "more natural delivery" may be stepping away from the security of childbirth in a hospital setting

Blunted erythropoietin production and decreased erythropoiesis in early pregnancy.

After decreasing in the first trimester of pregnancy, the total red blood cell mass increases in the second and third trimesters to peak at term at about 120% to 125% of nonpregnant values, but how this is brought about by changes in the rate of erythropoiesis is not known. We evaluated erythropoiesis by measuring serum transferrin receptor (TfR) levels in 406 women during normal pregnancy (N = 317), at delivery (N = 63), or in the early postpartum (N = 27). Despite the presence of the placenta and the frequent occurrence of iron deficiency, TfR levels remained low in the first two trimesters and increased in the third trimester and at delivery. To explain why erythropoiesic activity was relatively low in early pregnancy, we also measured serum immunoreactive erythropoietin (Epo) in relation to the degree of anemia. There was a very strong correlation between serum TfR and Epo levels in the entire group (r = .59, P less than .0001) as well as in each period of pregnancy. Epo levels remained low for the degree of anemia and did not correlate with hematocrit in the first two trimesters, but recovered afterwards. In the early postpartum, Epo production and erythropoiesis were normal. We conclude that: (1) erythropoiesis is decreased in the first part of pregnancy but increases afterwards; and (2) blunted Epo production in early pregnancy could be responsible for that observation

Medical Disorders Which Interfere with Pregnancy

peer reviewedDuring pregnancy, the future mother can develop several different diseases. Most of them have a benign prognosis. Cyanotic heart disease, at least when it is accompanied by significant pulmonary hypertension or induces a functional class IV represents a contra-indication to pregnancy. Pregnancy cardiomyopathy generally carries a poor prognosis and may be responsible for the mother's death. Herpes virus pneumopathy can also be extremely dangerous. Lupus erythematosus represents a factor of guarded prognosis for the outcome of pregnancy; discontinuation of the latter should be seriously considered. Hepatic steatosis which is a rare diagnosis must be distinguished from Hellp syndrome in which the maternal prognosis is much better. In this review, we shall briefly discuss various medical diseases which may have a deleterious influence on the evolution of pregnancy or on the foetus. These deleterious influences can be direct, i.e. due to the disease, or indirect, i.e. due to the therapy. We shall successively consider several neurological, cardiological, pulmonary, dermatological and digestive diseases. We shall not take into account viral infections or infections in general, diabetes mellitus or the various vasculo-renal syndromes

Psychosocial Environment and Premature Birth

peer reviewedFor about twenty years, prematurity has been the subject of many preventive actions. In spite of the elaboration of different screening programmes, preterm deliveries rate doesn't decrease. Some somatic risk factors are now known and are the subject of an unconditional screening in prenatal consultation. However we consider that the etiology of many preterm deliveries remain unknown and 55% of preterm cases could be idiopathic without any explanation of pathological order. The clinical observation suggests the existence of a link between preterm delivery and the psychosocial environment of the pregnant woman. According to that suggestion, they are now making a study in the university obstetrical service of the CHR Citadelle (Liege). The first part of the research has enabled to identify different risk factors such as: illegitimate pregnancy, future mother living alone, unemployed husband, no wage, stress, earlier miscarriage, social isolation, less than 2 years between 2 babies, bad satisfying pregnancy on a psychological and/or physical point of view. According to the study and literature results, a psychosocial risk screening overview has been elaborated. It would permit to identify the cases leading surely to a preterm delivery. That study is financed by a convention between the "Ministere de la Culture et des Affaires sociales de la Communaute francaise"

The Effects of Labor Induction on the Progress of Childbirth

peer reviewedLabour induction has become a common practice. Given the significant number of induced deliveries carried out each year, it is important to know the consequences of this induction policy. The effects of labour induction on the childbirth are still the subject of considerable controversy. The increase of the caesarean and instrumental extraction rates has already been emphasized in previous studies. This article is based on an analysis of 10,045 deliveries carried out in the CHR Obstetrical Clinic of La Citadelle, between 1991 and 1997. The conclusions are instructive. Thus a departmental policy of setting an induction level of 35% will allocate 2/3 of the workload between 8:00 AM and 8:00 PM during the week, with a preponderance on Friday. The Caesarean rate is not increased but peridurals and recourse to instrumental extraction are more frequent

Hellp Syndrome

peer reviewedThe HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelet count) is a clinical expression of a multilayered disease whose central pathophysiology is abnormal placentation. Clinical research aims logically to search for new predictive and specific markers for the early identification of pregnant women at risk of developing a HELLP syndrome, the most common cause of feto-maternal mortality and morbidity

sports and Pregnancy

peer reviewedPregnant women consult often their obstetricians for counselling about their way of living. Particularly answering questions concerning physical activity and sports during pregnancy require a profound knowledge on the physiological adaptations of pregnancy and, on the other hand, on performance and sports physiology. On the basis of the current state of research, physical exercise and sport are to be recommended during pregnancy so long as women are aware of potential dangers and contraindications. Maternal benefits and fetal benefits have today been demonstrated

Prevention of Prematurity in the French Community at the Approach of the Year 2000

peer reviewedThe actual results confirm the dominating influence of psychosocial factors on prematurity and low birth weight. The study performed in Liege indicates that these factors must be taken into account for better care of the future mother. The systematic use of a prenatal questionnaire on psychosocial factors draws attention towards the personal situation of the future mother. Detection of some organic or psychosocial risk factors must prompt prophylactic measures even in the absence of any sign of pathologies. Prevention of prematurity has, over the last 30 years, been the primary objective of prenatal follow-up. Its importance must be further emphasized