Whole Period Of Pregnancy Research Articles

On certain characteristics of higher nervous activity in adult animals antenatally exposed to ionizing radiation

Female albino rats were daily X-ray irradiated during the whole period of pregnancy in a dose of 1 r. After establishment of the coitus date by the presence of spermatozoa in the vaginal smear they were irradiated 20 days in succession, the total dose being 20 r. A study was made of the higher nervous activity of adult rats subjected to such irradiation during the whole period of embryonic development. There was some reduction in the strength of the main nervous processes in the antenatally irradiated animals in comparison with controls. The following was noted: a slower adaptation to the experimental surrounding environment, retarded conditioned reflex elaboration, prolongation of the latent periods and diminution of the positive conditioned reflex values. In these rats a more frequent loss of conditioned reflexes was noted. The functional tests with caffeine and starvation also point to the reduction of the stimulation and inhibition processes. The brain of the irradiated rats is of low weight and its cortex in the frontal portions is thin.

Localization of glycogen in the human placenta

Glycogen was determined by the Bauer-Feulgen method in the chorion and placenta of 4- to 40-weeks-pregnant women. It could be detected through the whole pregnancy in the ectodermal epithelium of the amnion and mesenchymal cells of the chorion laeve, extraplacental chorion, and amnion. Glycogen was also found throughout the entire cross section of the umbilical cord up to the 16th week inclusive; at the 20th week of pregnancy glycogen was determined only in the wall of the umbilical vessels with an insignificant spread beyond the muscular layer of the umbilical vein. With the progress of pregnancy the amount of glycogen in the cellular nodules increased, but in the last third of pregnancy, with the rise of the fibrinoid content, the amount of glycogen in the cellular nodules began to drop; at the 40th week of pregnancy it could be detected only in small amounts between the cells. The glycogen level in the stroma of the villi was low at first, but rose later; large amounts of glycogen were found in the stroma of the larger and stem villi during the last half of pregnancy; it was almost entirely absent in the stroma of smaller villi. Glycogen was revealed in the Langhans' cells throughout the whole period of pregnancy, whereas in the syncitial layer of the trophoblast it was absent altogether.

A study of nitrogen metabolism in the dairy cow

This communication deals with the results of two experiments in which the “nitrogen-balance,” or difference between nitrogen-consumption and nitrogen-excretion by the cow, has been studied over prolonged periods, starting with the “dry” cow, not in calf, proceeding through the whole period of pregnancy and well into the period of active lactation.Experiment 1 was performed throughout with the two cows, “dry” and not in calf, receiving a basal ration of hay to which was added increasing amounts of maize meal with a view to securing a progressively increasing consumption of nitrogen. This experiment lasted 196 days, during which period determinations of the nitrogen-balance were made on 90 days.Experiment 2 was carried out similarly with two cows, and covered a period of 722 days, including 546 days on which determinations of the nitrogen-balance were made. Throughout the whole of this period one cow (Cow C) was maintained “dry” and not in calf, as control cow, whilst the other cow (Cow D) after 302 days became pregnant and its record was followed throughout the stages of pregnancy and parturition and for the first 136 days of active lactation.The outstanding features of the results are as follows:(1) With the progressive increase of nitrogen-consumption beyond the fundamental requirements of the dry cow the rate of nitrogen-retention steadily increases to a maximum and then falls. The maximum appears to be attained under the conditions of our experiment with a protein-supply in the neighbourhood of 2·4 kg. crude protein per 1000 kg. live-weight. There are indications that this figure may be independent of the nature of the foods fed along with hay.(2) When the cow is maintained upon a ration which causes an initial nitrogen-retention the rate of retention falls steadily, but a very prolonged period—up to 90–100 days—may be necessary before nitrogenequilibrium is attained.(3) Even after nitrogen-equilibrium is established and a relatively constant nitrogen-consumption is maintained, there may arise from time to time considerable deviations from equilibrium either in the positive or negative direction. It would appear therefore that for reliable work of this character long experimental periods are essential.(4) The very earliest stages of pregnancy are marked by a profound disturbance of nitrogen metabolism, the requirement for maintenance of nitrogen-equilibrium being very sensibly increased. This additional requirement persists at a steadily reduced rate for some 15 to 20 weeks, after which it is very small. Over the whole period of pregnancy the average rate of nitrogen-retention was only about 2·4 gm. per day.(5) During parturition and for a few days subsequently the output of nitrogen is very great and more than can be restored rapidly by food-consumption. With the experimental cow, giving barely three gallons of milk per day at most, some two to three weeks elapsed after calving before nitrogen-equilibrium was restored.(6) It would appear that to maintain nitrogen-equilibrium during lactation, the food must supply from twice to three times the amount of nitrogen secreted in the milk, in addition to that required for the maintenance of equilibrium in the “dry” state. This represents a food-consumption which would be difficult to attain in the case of cows giving large yields of milk, and accounts for the familiar difficulty of maintaining the “condition” of such cows in the earlier stages of lactation.

THE NERVOUS ELEMENT IN THE VOMITING OF PREGNANCY.Read before the Chicago Medical Society.

<i>Mr. President and Fellow-Members:</i> In presenting this paper I do not hope to advance any radically new ideas, but rather to emphasize certain facts in regard to the nervous element in the vomiting of pregnancy which seem to have been indifferently considered throughout the voluminous literature upon the subject. It is surprising, as well as unfortunate, that so many physicians look upon the vomiting of pregnancy as a trifling matter. One writer says "that although the morning sickness sometimes persists during the whole period of pregnancy, it remains endurable, causing the patient annoyance rather than injury. The digestive functions remain more or less normal, and the vitality of the patient is not essentially impaired." Such has not been the result of my own observation. The distress alone, in even the mildest cases, is a constant tax upon the woman's nerves, and as a result she is less able to endure

VOMITING OF PREGNANCY; ITS ETIOLOGY AND TREATMENT.Read before the Allegheny County Medical Society, June 16, 1891.

Pregnancy, as a rule, is complicated with a variety of disorders, which, though in many instances causing much discomfort, are termed physiological as long as they are not associated with serious disturbances of the organism. Derangements of the gastro-intestinal canal, nausea and vomiting, to the consideration of which I invite your attention to-night, are such a regular occurrence during the early period of pregnancy that experienced women consider them as positive signs of conception. The so-called morning sickness—nausea and vomiting early in the morning, or even after meals, during the first few months of gestation—have, in the large majority of cases, no effect either upon the course of pregnancy or upon the health of women. Although the ordinary morning sickness sometimes persists during the whole period of pregnancy, it remains endurable, causing the patient rather annoyance than injury. There are intermissions, either spontaneously or the consequence of some treatment; the