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The wide-spread treatment of thermally activated unpinning of dislocations from point obstacles in terms of the absolute rate theory is criticized. In particular, doubts are raised about the validity of the assumption that a thermodynamic equilibrium distribution is established between the equilibrium state of a pinned dislocation and its saddle-point configuration. In analogy to Rice's dynamical theory of diffusion an alternative approach to dislocation unpinning is suggested, which does not make use of this assumption and which furthermore accounts for unpinning transitions by-passing the saddle-point configuration. Die Behandlung der thermisch aktivierten Versetzungsentankerung von atomaren Fehlstellen im Rahmen der absoluten Ratentheorie wird kritisiert. Insbesondere wird die Annahme bemangelt, das sich zwischen dem Gleichgewichtszustand einer verankerten Versetzung und ihrer Sattelpunktslage eine thermodynamische Gleichgewichtsverteilung einstellen soll. In Analogie zur dynamischen Diffusionstheorie von Rice wird eine Theorie der Versetzungsentankerung entwickelt, welche von dieser Annahme keinen Gebrauch macht und uberdies der Entankerung uber Nicht-Gleichgewichtszwischenzustande Rechnung tragt.

Within the framework of the vibrating-string model the frequency of thermally activated unpinning of dislocations from point obstacles is calculated with the aid of a dynamical theory. It is found that the unpinning frequency Γ has the form of an Arrhenius equation, Γ = Γ0e−ΔG/kT, where ΔG is the portion of the free enthalpy of activation which may be obtained by means of elasticity theory using isothermal elastic constants. The pre-exponential factor Γ0 is shown to decrease with increasing length of the pinned dislocation segments, contrary to the result obtained on the basis of the absolute rate theory. Im Rahmen des Saitenmodells wird die Frequenz der thermisch aktivierten Entankerung von Versetzungen von Punktfehlern mit Hilfe einer dynamischen Theorie berechnet. Es zeigt sich, das die Entankerungsfrequenz Γ die Gestalt einer Arrhenius-Gleichung hat, Γ = Γ0e−ΔG/kT, wobei ΔG den Anteil der freien Aktivierungsenthalpie darstellt, welcher mit Hilfe der Elastizitatstheorie unter Verwendung isothermer elastischer Konstanten berechnet werden kann. Der Vorfaktor Γ0 nimmt mit zunehmender Lange der verankerten Versetzungssegmente ab. Dies steht im Gegensatz zu dem Resultat, welches sich aus der absoluten Ratentheorie ergibt.

Primary prostaglandins have been measured by radioimmunoassay in the amniotic fluid of 80 patients. In late pregnancy, PGE2 was higher than PGF2alpha with an increase around 36 weeks (378 +/- 71 pg. per milliliter) without significant modification until term. PGF2alpha increased too, but only significantly at term. During spontaneous labor, PGE2 and PGF2alpha were higher than before the onset of labor. Through serial determinations in five patients, two steps can be distinguished: the first one with stable levels but large oscillations of PGE2 and PGF2alpha and the second one starting at a variable stage of cervical dilatation with inversion of PGE2/PGF2alpha ratio (less than 1 and followed by an increase of both compounds more pronounced for PGF2alpha. It appears that PGE2 is concerned with the initiation of parturition while both PG's and mainly PGF2alpha are in relation to the contractions and the duration of labor.

The strength of junction reactions with the dislocation forest for moving dislocations with 30° and 60° orientation is calculated following the treatment of Schoeck and Frydman for 0° and 90° dislocations. The flow stress can be expressed by τ = αGb(ϱ)1/2 where α ranges from 0.26 to 0.42. Of all moving dislocations, 30° dislocations encounter the weakest resistance due to forest intersection. Die Starke von Reaktionen beweglicher Versetzungen des Charakters 30° und 60° mit dem Versetzungswald wird berechnet nach der Methode von Schoeck und Frydman fur 0°-und 90°-Versetzungen. Die Fliesspannung kann in der Form τ = αGb(ϱ)1/2 mit α von 0,26 bis 0,42 dargestellt werden. Von allen bewegten Versetzungen treffen 30°-Versetzungen auf den geringsten Widerstand beim Durchschneiden des Waldes.

During plastic deformation of crystals edge dislocations containing large jogs may be generated by cross-slip processes of screw dislocations. A drag on these edge dislocations results in cases in which the resistance to dislocation motion is predominent at the jog. This concept is discussed with regard to the Peierls stress and a selective interaction with point defects. The model explains the thermal component of the flow stress in NaCl-crystals at room temperature and may be extended to crystals with hexagonal structure. Furthermore, the occurrence of broad deformation-induced internal friction peaks is predicted for crystals in which the discussed drag mechanisms are operating.

The formation of junctions between a moving dislocation and the trees of a dislocation forest has been calculated for f.c.c. crystals. In contrast to previous estimates the concept of the orientation-dependent line energy and a more realistic averaging procedure was used. In a random forest in which the tree length is equal to the tree separation only about 20% of the trees form junctions. The stress to overcome the junctions is higher for screw dislocations than for edges but the exact values depend on the nature of the forest. Die Bildung von Versetzungsreaktionen zwischen einer bewegten Versetzung und den Baumen eines Versetzungswaldes wurde fur k.f.z. Kristalle berechnet. Im Gegensatz zu fruheren Abschatzungen wurde die Orientierungsabhangigkeit der Linienenergie berucksichtigt und eine realistischere Mittelung vorgenommen. In einem regellosen Wald, dessen Baumlange gleich dem Baumabstand ist, reagieren nur etwa 20% der Baume. Die Spannung, um die Rekombinationen aufzulosen, ist hoher fur Schraubenversetzungen als fur Stufenversetzungen. Die genauen Werte hangen jedoch von der Natur des Waldes ab.

Luteinizing hormone-releasing hormone (LH-RH) agonists are being increasingly used in ovulation stimulation protocols in IVF programs. The results of two methods of utilization of LH-RH agonists are compared. There was difference in the ovarian response on the day of human chorionic gonadotropin (hCG) higher in the short protocol (69% vs 56%, P less than 0.001). The ongoing pregnancy rate per treatment cycle was similar in both groups (18% in the long protocol and 16% in the short protocol).

21 parturients, showing in most of cases either high blood pressure badly controlled or a "real" out of date term, have undergone a peridural analgesia of first intention in labour induction. All these patients were considered to be uninducable according to Bishop score. After an injection of adrenalinized bupivacaïne, either 0.25% or 0.375% rupture depending on state of cervix of membranes occurred in most cases 6 hours after peridural analgesia. The mean between onset of analgesia and delivery was 17 h and the mean time between induction with ocytocin to birth 5 h 37 min. 16 parturients gave birth per vaginam, 9 of which spontaneously 5 have undergone caesarian section because of a non lack of dilatation or foetal distress. Children at birth, at the 2nd and the 24th hour were all healthy.

Ovulation occurs between 37 and 40 h after the beginning of the luteinizing hormone (LH) discharge in the blood (Testart and Frydman 1982a) or after an injection of human chorionic gonadotropin (hCG) (Testart and Frydman 1982a; Edwards and Steptoe 1975). Between 25 and 35 h after the onset of the LH surge or the hCG injection the oocyte maturation proceeds from prophase I to stage metaphase II (Testart et al. 1982b; Steptoe and Edwards 1970). During these 10 h or so, the only changes in hormonal concentrations of the follicular fluid concern androgens, which decrease slightly (Testart et al. 1982c). Thus the hormonal characteristics of the follicles at the time of ovulation are similar to those during the oocyte maturation process.

The authors formulate some safety rules in view of two case histories of bowel complications following voluntary termination of pregnancy using suction techniques. Where it is not certain that a perforation has occurred laparoscopy is necessary. When perforation has been confirmed a laparotomy is undertaken in order to check the state of the bowel throughout its length, because when lesions of the digestive tract are treated rapidly the results are good whereas when they have to be treated for peritonitis the outlook is poor.

Immunointerruption of pregnancy consists of preventing pregnancy or terminating it at an early stage through antibodies. The antibodies may be obtained after administration of vaccine to induce their formation through active immunization, or by direct injection through passive immunization. Antigens that could potentially be used are found in sperm, the zona pellucida, and reproductive hormones, especially the chorionic gonadotropins. The sperm antigens are basically enzymes such as hyaluronidase and accrosine. 3 glucoproteins have been identified in the zona pellucida of mice and pigs. In vitro studies have shown that fertilization can be prevented if eggs are exposed to antizona-pellucida antibodies along with sperm. Active immunization could give longer term results, but ovarian function could also be affected if the antigens weren't purified. Much research has been devoted to identifying human embryonic antigens through analysis of the proteins of the cells of embryonic teratocarcinoma. Among placental antigens, the glucoprotein SP1 synthesized by the trophoblast is under study. Anti-SP1 antibodies appear to cause abortion in monkeys, but knowledge of these antigens is still fragmentary. Various reproductive hormones have been studied, but too many undesirable effects could result from the use of luteinizing hormone, luteinizing hormone releasing hormone, follicle stimulation hormone, or steroids. Human chorionic gonadotropin (hCG), however, is more promising. It is a glucoprotein formed of alpha and beta subunits, both of which are needed for hCG to interact with its receptor. The alpha subunit has the same sequence as that of other hormones of the same species, but the beta subunit is specific to each hormone. Studies are underway to determine the site of amino acids and peptide sequences capable of inducing an anti-hCG response which would inactivate the biological activity of hCG. Different teams have used synthetic peptides analogous to sequences of beta-hCG or fragments obtained by enzymatic cleavage of natural hCG to block pregnancy in rats and baboons. The presence of antibodies can block pregnancy without disturbing ovulation or modifying menstrual regularity. No toxic or secondary effect has been observed in animals. A multicenter phase 1 test using beta-hCG coupled with tetanus antitoxin caused almost all the women participating to develop antibeta-hCG and antitetanus anatoxin antibodies, but titres of antibodies varied greatly between different women, required 5-6 months to develop, and declined rapidly thereafter. Several pregnancies were observed, especially in women with low titres of antibodies. The approach of passive immunization through direct injection of antibodies has met with numerous obstacles, including lack of success in producing human monoclonal antibodies. Although a 2nd generation of vaccines in under study, the potential role of immunointerruption of pregnancy in fertility regulation remains to be clarified.

We here report the results of our first attempts at fertilising the human oocyte in vitro. No external hormonal stimulation was used to induce follicular growth or maturation of the oocyte. Nine oocytes were obtained laparoscopically in ten women in the pre-ovulation hours. They were incubated in a synthetic culture medium in the presence of freshly ejaculated spermatozoa. Five oocytes were fertilised normally, of which three were cultured just up to the stage of 4-6 blastomeres. The three failures of fertilisation can be put down to poor quality of the gametes. The discussion is carried on about the quality of the oocyte and of the embryo and justifies further studies to deepen our knowledge before embarking on embryo transplant.

The fact that 20% of the abortion requests at Antoine-Béclère Maternity Hospital in 1978 came from women under 20 years of age makes it clear that teenagers are insufficiently informed and familiar with contraception and makes it obvious that a change is necessary. The different types of contraception and the conditions of choice and application are briefly described.

Ovulation inductors within the context of an in vitro fertilization program are mainly used in order to be able to know the exact time of the rupture of the follicle and to recover several mature oocytes. In this paper the Author describes the types of ovulation inductors used at present and underlines the fact that the study of the metabolism of the embryo will be a future aim for a better understanding of the success of in vitro fertilization.

The lipid content of human follicles within 6 h of ovulation was determined. Levels for triglycerides, phospholipids, and total cholesterol were 1/4 to 1/3 of those in serum. An uncommonly high level of free cholesterol was observed, possibly resulting from a high synthetic rate by the granulosa. Follicular lipids appear to be of serum origin since the relative proportions of the various fatty acids are the same. Arachidonic acid was not found to be present at the high levels reported for "large" porcine follicles, possibly due to its active utilization in the synthesis of prostaglandins necessary for the ovulation process. Precise timing relative to ovulation is clearly essential for follicular classification in order to distinguish between before and after the triggering of the ovulation process. A possible role for lipids in the induction of capacitation is proposed.

Inhibin-like activity as well as estradiol-17 beta and progesterone content were assayed in human follicular fluid obtained at different stages of the periovulatory period. Between the start of the midcycle estrogen surge in plasma and the subsequent gonadotrophin peak, follicular fluid was found to contain similar levels of estradiol-17 beta and progesterone (8.2 pmol/microliter) and to induce a marked (44%) inhibition of gonadotrophin-releasing hormone-stimulated release of FSH. The midcycle gonadotrophin peak was characterized by a drop in estradiol-17 beta levels and a tripling in progesterone levels, whereas inhibin-like activity fell to almost half the previous value.

Since 1960, laparoscopy under local anaesthesia has been gradually abandoned in France and until now oocytes for in vitro fertilization were collected under general anaesthesia, thus increasing the risk of allergic reactions to anaesthesia in these patients who usually undergo several operations. From February to May, 1983, at the Antoine Béclère Maternity, Paris, 50 laparoscopies were performed under local anaesthesia with lidocaine combined with neuroleptanalgesia with diazepam and fentanyl. The procedure was uneventful in 94% of the cases and only 3 women required general anaesthesia. At least one mature oocyte was collected in 46 of these 50 women and 4 pregnancies have already been recorded. Local anaesthesia enables the woman to participate fully in this first stage of in vitro fertilization, increases the out-patient activities of the hospital unit and reduces the cost of in vitro fertilization.

We have carried out an enquiry into feeding in mothers in whom failure of intra-uterine growth of the fetus has been suspected around the thirtieth week of amenorrhoea according to clinical criteria (23 cases with a mean birth weight of 2564 g). We used a special questionnaire in the third trimester of pregnancy. The special feature of these failures of intra-uterine growth were that they did not appear to have any known cause. The calory intake of the mother was compared at the same time with a control group (39 cases where the mean birth weight was 3333 g). A significant difference was found in the calory intake (2241 Kcal as against 2553 Kcal) and this was especially connected with a low carbohydrate intake. The consequences of this deficiency in maternal carbohydrates on the birth weights of the newborn is discussed taking into account other factors that could interfere with fetal growth.

It is possible with echotomography to make out fetal ascites in the last months of pregnancy. One of the causes of combined fetal ascites and hydramnios among several other possible ones is primary meconium peritonitis, which diagnosis can be confirmed after birth.

A retrospective study of triplet pregnancies is presented. Data concerning 24 triplet pregnancies which were followed up to delivery and for a period of 11 years afterwards at the Maternity Center of the Antoine Beclere Hospital, are analysed. Early diagnosis of triplet pregnancy leads to a strong prognostic indication for prematurity. This allows time to institute preventive measures principally by reducing maternal physical activity. Because of the establishment of specific prenatal surveillance of the mothers, the rate of prematurity in triplet pregnancies be notably lowered. The mean gestational age at delivery was 33.9 weeks. The use of corticosteroid therapy between 28 and 34 weeks of gestation seems to helps prevent hyaline membrane diseases. Delivery is performed by elective cesarean section. The perinatal mortality rate was 6%.

Sexually transmissible diseases affect adolescents as well as the rest of the French population. It is difficult to estimate their frequency from official statistics since not all cases are reported. However, the recrudescence of these diseases is certain, with adolescents representing 10 to 50 0/00 of all cases. These diseases threaten the obstetrical and gynecologic future of adolescents and cost society a great deal of money. In the combat against them, prevention and public education are as important as early screening.

Some biochemical and biophysical variables of human follicular fluid have been studied both in normal women after the LH peak (preovulatory follicles) and in women treated with clomiphene and hCG (clomiphene treated follicles). The results showed that lactate and glucose levels are different from those found in serum but are not influenced by the clomiphene treatments. Osmolarity and enzymatic contents are neither different from those of serum nor modified by the hormonal treatments. The transfer of water across the follicle wall was found to be closely regulated because only slight variations were observed in the wide range of volumes collected in the samples examined.

In an attempt to improve survival rates in Stage III, grade III-IV ovarian carcinoma (5 years survival rate less than 10%), we have tested the feasibility of a combined modality approach in 10 patients. Five of the 10 patients have been treated with surgery, chemotherapy, second look laparotomy, whole abdominopelvic irradiation and chemotherapy. Three patients are alive without evidence of disease (range 24 to 54 months) after entering the combined programme. We conclude that a combined modality therapy can be safely delivered. The acute toxic effects were not more frequent or more severe than with other therapeutic approaches. These results are compared with published reports in the literature.

The implantation of “good quality” embryos into a “receptive” uterus is a fundamental requirement for the establishment of pregnancy following both in-vivo and in-vitro fertilisation. However, unlike certain other aspects of reproduction, our knowledge of the peri-implantation period remains limited (Hearn 1986). Although we have been able to promote follicular growth and ovulation in women for nearly 30 years (Gemzell et al. 1958), our capacity to influence implantation in a positive sense is negligible. Scientific experimentation in this area is limited, and the multifactorial nature of embryo-uterine interactions greatly increases the complexity of the subject.

Predicting ovulation is the basis on which the fertile period is determined. When we carried out observations on 60 spontaneous cycles it was possible to detect with precision the discharge of LH which would produce ovulation by taking series of plasma levels of LH. The start is defined as the time when the level of LH becomes 180% greater than the mean level observed in the previous 24 hours. Ovulation occurs between 37 and 39 hours after this threshold has been crossed. The discharge of LH is the most constant criterion and the most precise one, and it does make it possible to work out the chronology of the events that precede ovulation. Ultrasound and estimation of levels of oestradiol in the plasma or in the urine do allow one to appreciate how the follicle is maturing.

The number of pregnancies in adolescents is increasing in most countries and represents a public health problem. Teenage pregnancies are in the high-risk group. However, early recognition and correct management make them as safe as those of older women except for two complications which seem to be peculiar to them: toxemia of pregnancy and premature delivery. In addition, a higher frequency of congenital defects of unknown etiology was observed in our study.

The authors report a case of successful pregnancy 8 years after surgery and chemotherapy for biliary cancer with secondaries in the liver. The authors, in considering this case, have analysed the sequelae of chemotherapy for cancer on fertility. They discuss the need to preserve the ability to produce oocytes in young women who need treatment for cancer.

Antibacterial activity of 22 amniotic fluids collected at different stage of pregnancy have been tested against different types of staphylococci: 209 P, 2961 and Escherichia Coli OMS and 83. At the same time zinc and phosphorus concentration in these fluids have been measured. 77 p. 100 of those fluids present an antibacterial activity, but no correlation has been found with their concentration in zinc and phosphorus. Probably this activity is multifactorial and further studies need to be done to identify the factor or factors responsible for that antibacterial activity.

Lysozyme content of 47 A.F. collected at different stages of pregnancy has been measured. At the same time creatinine concentrations of 33 of those A.F. have been measured. Lysozyme content increases with the progress of the pregnancy. A similar increase is apparent when lysozyme concentration is correlated with A.F. creatinine.

For dystoctic deliveries peridural analgesia with bupivacaine 0.25% was compared with bupivacaine 0.375%, without adrenalin. Shortening of the delivery time in cases of stagnation of dilatation, was obtained with bupivacaine 0.375%: 181 mn in the average instead of 276 mn with bupivacaine 0.25% (p = 0.05). In the case of a cervical spasm, there was release of the contraction with return of a normal dilatation leading to a shorter labour: 188 mn in the average against 340 mn (p = 0.02) with the 0.25% solution. Apgar scores were similar in both series.

Spontaneous expulsion of a human ovum fecundated in vitro and transferred into the uterus occurred after 10 1/2 weeks of amenorrhoea. The oocyte had been collected after stimulation by human menopausal and chorionic gonadotrophins (hMG and hCG). The techniques of pre-ovulatory oocyte collection, fecundation, in vitro culture and of reimplantation of the embryo are briefly described.

About 10 p. cent of pregnancies which develop after in vitro fertilization and implantation of the ovum in the uterus are extrauterine. This surprising statement evokes several explanations and the authors consider that their prevention by preliminary tubal sterilization is quite excessive.

Rapid radio-immune assaying of LH was carried out four times daily on 52 women in the preovulatory phase of the cycle. This method enables the precise detection of the LH surge and recovery of the mature oocyte by laparoscopic aspiration of the follicular content, just before ovulation, which is between 28 and 36 hours after the start of the LH surge. The oocytes was recovered in 27 out of 41 patients with a normal cycle (66%). The rate of recovery per follicle aspirated is comparable in a natural cycle to that after treatment with Clomid (80 to 84%).

Uterine aspiration, which has been under development for nearly a century, is the most common technique at present for early abortion. The procedure should be aseptic, beginning with placement of the patient in the correct position, cervical dilatation through introduction of graduated sounds, introduction of a cannula appropriately sized for the gestational age, and the aspiration itself. The products of conception should always be examined; occasionally it indicates pathology such as ectopic pregnancy or hydatidiform mole. Use of a sequential oral contraceptive after the procedure speeds uterine recovery. Abortion patients should undergo interviews separately from the abortion procedure to affirm their desire for the operation and to clear up any misconceptions. During the interview the procedure is explained and a climate of trust is established. The medical examination and patient history are undertaken before a definite decision is made, and the reception, medical examination, and interview do not occur on the same day, permitting time for reflection and possible change of plans. The anesthesia to be used is determined in part by the patient's preference and by the gestational age. For pregnancies of less than 6 weeks, all anesthesia can be dispensed with as long as the patient is reassured, procedures are carefully explained to her, and the operator avoids the least trauma. Administration of a sedative is usually practiced. Paracervical block is the most commonly utilized anesthesia, but should be avoided if allergies, anatomic pecularities, or behavioral difficulties are present. General anesthesia may be chosen for early abortion under some circumstances and may be preferable in pregnancies of over 9-10 weeks to facilitate cervical dilatation. Depending on gestational age, uterine volume, and other factors, aspiration using a syringe or a source of electrical or mechanical power may be preferred.

Quadruplets born at 36 weeks gestation were severely hyponatraemic. The mother had been given a sodium deficient diet for the majority of pregnancy and she herself was also hyponatraemic with hyperaldosteronism. This patient illustrates the problems of sodium restriction during pregnancy and the need for its supervision.

In cases of congenital absence of vas deferens (9 patients) or after failure of previous epididymovasostomy (2 patients), in vitro fertilization (IVF) was attempted with spermatozoa surgically obtained at the epididymal caput level. These sperm populations showed little progressive motility (5.9 +/- 6.5%) and an marked necrozoospermia (19.3 +/- 17.4%). Stimulation by caffeine (4.5 mM) alone or associated with heterologue normal seminal fluid resulted in most of the cases in an initiation of motility with an improvement of the progressive velocity. In 9 IVF attempts, 31 mature oocytes were inseminated with 5.10(3) to 1.5.10(6) motile spermatozoa. The dynamic characteristics in 3 inseminated sperm populations were Vp (24.2 +/- 8.3 microns/s), Ah (8.6 +/- 2.0 microns) at room temperature. Sperm binding to zona pellucida was decreased (0 to about 20 spermatozoa per oocyte) and there was no fertilization. In the same period, 21 attempts of intra uterine insemination and 14 attempts of intracervical inseminations were made in 5 couples who remained infertile after patent high epididymovasostomy (4) or vasovasostomy (1) and having immature spermatozoa stimulated as previously described. Antisperm antibodies were detected on the ejaculated spermatozoa in four men. No pregnancy was obtained with these immature stimulated spermatozoa. The fertility of the female partners was confirmed in 3 women after insemination with donor sperm.

The hormone state of development in the late preovulatory phase is described in its relationship to the start of the LH surge which occurs 37-39 hours before ovulation. No precise relationship has been found between the oestradiol (E2) peak in the plasma and that which occurs before ovulation. All the same, the succession of hormone events that have been observed in 77 spontaneous cycles is the following: the level of E2 suddenly rises between 35 and 30 hours before the ovulatory discharge and this rise is immediately followed by a rise in the level of LH. Then the plasma concentration of 17-hydroxyprogesterone (17-OHP) increases 5 hours before the LH surge. In the preovulatory follicle 5 hours after the start of the LH surge, a drop in the level of E2 and a rise in the level of progesterone is noted. Concentrations of androgens only lessen in the last 12 hours before ovulation whereas the level of 17-OHP stays stable. We have thus been able to work out the sequence of plasma hormone phenomena that occur in determining whether a preovulatory gonadotrophic surge will occur. We have described the hormone levels in follicular fluid immediately before spontaneous ovulation. These findings will be able to serve as a reference to evaluate the quality of the late preovulatory phase in abnormal cycles or in cycles that have been induced.

One of the complications of therapeutic termination of pregnancy is the complete retention of the embryo. The authors present four cases of repeated failure to evacuate the uterus associated with multiple fibroids or a malformation of the uterus. The use of RU 486 to soften the cervix and to allow it to dilate spontaneously made it possible in each case to aspirate the products completely. This action on the cervix of RU 486 could be used to make it easier to terminate early pregnancies up to the 12th week and particularly when there is associated uterine pathology.