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Biomedical subjects

I Brosens

Publications and source records attributed to I Brosens.

At least 73 records · Page 4Linked to original sources
PubMed1985

The effect of training in microsurgery.

One of the most important and fundamental prerequisites for successful microsurgery is serious and adequate training. This article presents the effect of microsurgical training on the functional end result of reanastomosis in the rabbit fallopian tube and evaluates the appropriate duration of laboratory training. In 50 New Zealand White female rabbits a microsurgical reanastomosis of the fallopian tube in its isthmic portion was performed. The rabbits were divided into five groups. In the first group only 30% of the rabbits conceived on the side operated on. The nidation index was only 0.269 as compared to 0.831 for the control side. Improvement in microsurgical skill following 100 isthmic anastomoses resulted in a 100% pregnancy rate for the last group. The nidation indexes in this group were the same on the side operated on and on the control side, 0.774 and 0.702, respectively. Scanning electron microscopic examination of the anastomosis site revealed a progressive increase in patency rate and in the amount of apposed mucosal folds in the three groups. A training program is recommended, which should bring about a nidation index and pregnancy rate that should not differ from the side operated on to the control side.

Animals↗
PubMed1985

The response of human endometriotic implants to the anti-progesterone steroid R 2323: a histologic and ultrastructural study.

The histology and ultrastructure of small endometriotic lesions were studied in 19 patients before and after hormonal therapy with the anti-progesterone steroid R 2323 (Gestrinone). Histologic results demonstrate that treatment of endometriosis with this steroid does not result in complete elimination of the endometriotic foci, although glandular proliferation and secretion are arrested in most implants. The ultrastructural results indicate that this inhibition of proliferation and secretion is related to an enhanced activity of the lysosomal system in the epithelial cells of some endometriotic foci. In other implants, or even in other cells of the same foci, epithelial cells with only a small amount of supranuclear cytoplasm but lacking lysosomes may be found. The morphologic data demonstrate that the cellular involutionary response to the antiprogesterone drug Gestrinone involves an activation of the lysosomal system, an abortive apocrine secretion of cell remnants and finally, in some implants, an extrusion of individual epithelial cells. Since this involutionary process of endometriotic cells mimics the pre-menstrual lysosomal degradation in the endometrium, it is suggested that the competitive binding of the antiprogesterone Gestrinone to the progesterone receptors of endometriotic epithelium may cause a cellular progesterone withdrawal effect.

Adult↗
PubMed1985

Training in tubal microsurgery.

The restoration of normal tubo-ovarian function was investigated in a training programme using oviduct anastomosis in the rabbit as an experimental model. Ovulation rate, pregnancy rate, nidation index, implantation failure index and degree of adhesions were used as parameters. More than 100 anastomoses had to be performed to reach a perfect degree of atraumatic, function-restoring surgery. It is concluded that the most difficult aspect in female infertility surgery is not the use of the operating microscope but the experience in applying the principles of atraumatic surgery.

Animals↗
PubMed1985

Sperm phagocytosis by corona cells in a human in vitro fertilization system.

Clumps of corona cells were separated from oocytes at the moment of fertilization control and were subsequently processed and cut into 1-mu sections to study their general morphologic patterns. This study revealed an extensive phagocytosis of spermatozoa by corona cells. Clumps of mural granulosa cells of comparable size, recovered from follicular aspirates and incubated with spermatozoa, did not show the same extent of phagocytotic activity. The different nature of extracellular material could prevent penetration of the granulosa cell masses and thus a close contact between spermatozoa and granulosa cells. In our limited number of studied cases there was no indication of an aberrant phagocytosis pattern in coronas from polyspermic eggs or from oocytes that did not become fertilized. On the other hand, sperm penetration, as revealed by the sperm/corona ratio, was significantly higher in coronas derived from polyspermic eggs compared with those from unfertilized oocytes.

Chorionic Gonadotropin↗
PubMed1985

Abnormal placentation.

It is only relatively recently that attention has been directed to studies of the uterine side of the placenta to look for possible defects that might explain otherwise inexplicable pregnancy complications. Preeclampsia and intrauterine fetal growth retardation are two such disorders, in which new information has come to light by the study of placental bed biopsies and occasional cesarean hysterectomy specimens. It will be less easy to apply these techniques to such problems as spontaneous abortion and antepartum hemorrhage, but reemphasizing what should be the self-evident importance of the establishment and development of the uteroplacental blood supply might help reorient thinking about these and other important complications of pregnancy. Fresh thoughts are required too about the etiology and natural history of ectopic pregnancy, not so much for its own sake but more because of what it tells us about nidation and placentation in general. It is now difficult to insist on stringent criteria for the endometrium in human gestation, with all that this implies for the woman under investigation for infertility, when in some circumstances these criteria are flouted in what should be an alien mucosa. Much more needs to be known about the promotion and control exercised over trophoblastic differentiation and migration and interaction with uterine tissues. The uterus certainly can no longer be considered an immunologically privileged site even were that privilege extended to the fallopian tube and, indeed, to the adnexa generally. The constraining influence of decidua, if indeed it has such a property, requires elucidation; it cannot be fortuitous that only in species with hemochorial placentation, characterized by migratory nonvillous trophoblast, is a true stromal decidua formed. This surely indicates that decidua has a major role to play in negotiating "the treaty of compromise" ultimately signed between fetal and maternal tissues and if such a treaty is not signed, or is broken, defective placentation and its consequences must follow.

Abortion, Spontaneous↗
PubMed1984

Microsurgery of endometriosis in infertile patients.

From January 1973 to December 1980, 176 infertile women with endometriosis were treated with atraumatic and microsurgical techniques. None of these patients received preoperative or postoperative antigonadotropin therapy. The degree of endometriosis in these patients was classified according to the scaling point system of The American Fertility Society. After 2 years the cumulative pregnancy rate of the severe group (40%) was not different from that of the mild (43%) or moderate group (45%). It is therefore suggested that the use of microsurgical techniques can improve the pregnancy outcome in patients with severe endometriosis.

Adult↗
PubMed1982

Ovarian transplantation by selective microvascular anastomoses in the rabbit.

Autotransplantation of the ovary by microvascular anastomoses was performed in 42 rabbits by three different procedures: orthotopic replantation with selective end-to-end anastomoses of the ovarian vessels; heterotopic transplantation in the groin area, with anastomosis of the ovarian vessels on the inferior epigastric vessels; heterotopic transplantation in the groin with the ovary included in a peritoneal sac to prevent adhesions. Three weeks later, at day 3 of a pseudo-pregnancy, the grafts were examined and morphology, presence of adhesions and ovulation were compared with those of a control group. The long-term vascular patency rate was 78%. The ovulation rate was 71.5% in the orthotopic group, 50% in the heterotopic group and 83.5% in the heterotopic group with the ovary in a peritoneal sac. Subcutaneous transplantation of the ovary within a peritoneal sac provides a new and useful experimental model for the study of tubo-ovarian function and for recovery of postovulatory oocytes.

Animals↗
PubMed1982

Ultrastructure of uteroplacental arteries.

Ultrastructural study of the placental bed spiral arteries confirms that non-villous cytotrophoblast is involved in the development of the physiological changes occurring in these vessels during normal pregnancy. The changes observed in the myometrial segments of the spiral arteries before the time of arrival of endovascular trophoblast but after the invasion of the myometrium by migrating interstitial trophoblast, are characterised by widening of the lumen, oedema of the intima, disruption of the elastica and widening of the intercellular spaces of the media. This vascular distension could facilitate the subsequent retrograde migration of endovascular trophoblast. The fetal cells migrate in the vessel lumen and infiltrate the subendothelial space causing further disruption of the arterial intima and media. The altered intima is subsequently recovered by the endothelium. In this way, the cytotrophoblast is incorporated into the wall of the placental bed spiral arteries which are converted from small muscular arteries into distended hyalinized tubes. In pregnancies complicated by preeclampsia and in some pregnancies complicated by fetal growth retardation, these physiological changes are largely restricted to the decidual segments leaving the myometrial segments unaffected. The lesion of acute atherosis is characterised by thickening of the intima and necrosis of the media. The intimal thickening is due to deposition of fibrin and other plasma constituents and migration into the intima of macrophages and myointimal cells which accumulate fat in their cytoplasm to become foam cells. Clinical and experimental studies indicate that these lesions can be initiated by several factors which cause endothelial injury.

Arteries↗
PubMed1981

Endometriosis.

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Endometriosis↗
PubMed1980

Tubal lesions subsequent to sterilization and their relation to fertility after attempts at reversal.

Tubal biopsy specimens were obtained at the time of tubal anastomosis in 26 previously sterilized women. Scanning electron microscopy showed that half the patients had abnormalities of tubal mucosa, including loss of mucosal folds, deciliation, and polyposis. These pathologic conditions, the morphologic features of which we describe, significantly increase in incidence the longer the time after sterilization. Our evidence suggests that the sooner reversal is performed after sterilization the greater the change of a successful intrauterine pregnancy.

Adult↗
PubMed1980

The human placental bed: electron microscopic study of trophoblastic invasion of spiral arteries.

During normal human pregnancy the spiral arteries of the placental bed became so greatly distended that they are capable of delivering a tenfold increase in the supply of blood required by the fetoplacental unit in the third trimester. Studies performed with the use of light and electron microscopes have shown remarkable structural alterations in the walls of these arteries at the end of normal human pregnancy. In order to evaluate the various hypotheses of the histogenesis of these vascular physiologic changes, the present study with light and electron microscopes was carried out on the spiral arteries during the second trimester of normal human pregnancy. Special attention was given to the intravascular migration of trophoblast, as well as to the consequent interaction between fetal and maternal tissues.

Arteries↗