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Biomedical subjects

P Wilkin

Publications and source records attributed to P Wilkin.

At least 19 recordsLinked to original sources
PubMed1992

Respiratory instability during sleep onset.

It has been hypothesized that regulatory control in the respiratory system is state dependent. According to this view respiratory instability during sleep onset is a consequence of repeated fluctuations in arousal state. However, these speculations are based primarily on measurements during stable sleep, not during sleep onset itself. The aim of the present study was to assess changes in ventilation and gas tensions during sleep onset as a function of arousal state. Twenty-one subjects (12 males and 9 females, mean age 20 yr) were assessed over an average of 11.3 sleep onsets. The subject's state was classified as alpha, theta, body movement, or stage 2 sleep, and expiratory tidal volume, minute ventilation, respiratory rate, and end-tidal CO2 and O2 were measured by means of a face mask, valve, and pneumotachograph on a breath-by-breath basis. Respiratory instability during sleep onset was found to be a result of two factors. The first factor was a between-state effect in which transitions from alpha to theta were associated with falls, and from theta to alpha with increases, in ventilation. The magnitude of the change was a positive function of metabolic drive at the time of the state change (as indicated by alveolar PCO2 and PO2 levels). The second was a within-state effect in which ventilation fell during consecutive alpha breaths and increased during consecutive theta breaths. These changes were due to the influence of the relative hyperventilation of the alpha state and the relative hypoventilation of the theta state on metabolic drive.

Adult↗
PubMed1990

Pathologic features of placentas from singleton pregnancies obtained by in vitro fertilization and embryo transfer.

Fifty placentas were collected at term from singleton pregnancies resulting from in vitro fertilization (IVF) and intrauterine embryo transfer. Their pathologic features were compared with those of a control group composed of 50 placentas obtained from spontaneous singleton pregnancies. The mean maternal age, mean gestational age, mean fetal weight, sex ratio, and rate of pregnancy complications did not differ. There was also no significant difference between the groups in the mean placental weight and in the incidence of placental pathologic lesions, including extended infarcts, massive perivillous fibrin depositions, chorioangiomas, and placental inflammatory lesions. The incidence of abnormal placental shapes was significantly (P less than .05) greater in the IVF group (22%) compared with the control group (6%). A significant (P less than .025) difference was observed between the groups in the distribution of umbilical cord insertions. The mean distance between the cord insertion and the closest placental margin was significantly (P less than .005) shorter in the group conceived by IVF (3.23 +/- 1.91 cm) than in the control group (4.54 +/- 2.42 cm). A relationship between these placental morphologic features and the superficial implantation and/or inadequate orientation of the blastocyst after IVF and intrauterine embryo transfer is proposed.

Adult↗
PubMed1989

Embryonic remnants of the umbilical cord: morphologic and clinical aspects.

Embryonic vestiges of the umbilical cord are classic findings in routine morphologic examination of the placenta. In order to evaluate their clinicopathologic significance, we examined samples from the fetal and placental ends of 1,000 umbilical cords and collected the principal clinical findings of the corresponding newborns. Microscopic evidence of embryonic remnants were found in 231 cases (23.1%) divided into remnants of the allantoic duct (63%), the omphalomesenteric duct (6.6%), and the embryonic vessels (30.4%), including one case of hemangioma and an accessory small artery. There were no significant clinical differences between the three vestigial groups, and no particular association with congenital malformations or perinatal complications. In 70.9% of the cases, the embryonic remnants were found at the fetal end of the umbilical cord, where most tumors of the cord develop.

Allantois↗
PubMed1989

[Ultrasonic study of the single umbilical artery syndrome. A series of 80 cases].

The authors report on 80 cases of the syndrome of a single umbilical artery (SUA) and compare the anatomo-clinical features with the abnormalities found on ultrasound. The clinical results confirm the information given in the literature which is that there is a higher incidence of poor intra-uterine fetal growth (36.4%), of prematurity (16.3%), of associated congenital abnormalities (42%) and of perinatal mortality (21.3%). Ultrasound examination makes it possible to screen for associated major fetal malformations (26.6%) and of most cases of intra-uterine growth retardation (28.3%). The ultrasound detection of the absence of one of the umbilical arteries and of the associated fetal abnormalities together with the techniques for sampling fetal cells now causes change in the approach to these high risk pregnancies on the cytogenetic level as on the perinatal handling of this syndrome.

Adolescent↗
PubMed1989

[Morphologic study of ultrasonic placental anomalies in the second half of pregnancy].

Fifty cases of placental lesions detected by sonography during the second half of pregnancy were pathologically investigated. Sonographic evaluation included the size of the lesion, its echogenicity on subsequent examinations and location in relation to the placental margin and umbilical cord insertions. Classical pathologic examination was performed after delivery to confirm the ultrasonographic findings. The echogenic pattern of these lesions was distinct from that of the rest of the placenta and the lesions were classified in two categories. The parenchymal lesions including 19 intervillous thrombosis, 14 caverns, 3 cases of hydatidiform changes, 2 infarcts, 1 septal cyst and one case of fibrin deposition and, the chorionic lesions including 5 subchorionic thrombosis, 3 cases of extrachorial placentas and 2 amniotic cysts. Therefore diagnostic ultrasound gives the clinician a unique opportunity to perform detailed examination of the placenta in vivo and can be an effective and non-invasive way to diagnose different types of lesions that are usually described in the post-partum by the pathologist.

Female↗
PubMed1988

Clinical and morphologic aspects of the vanishing twin phenomenon.

The pathologic findings in placentas from ten multiple gestations complicated by the so-called vanishing twin phenomenon were studied to confirm the ultrasonographic evidence. Five pregnancies resulted from in vitro fertilization and embryo transfer, and five conceptions were spontaneous. The pregnancies were studied by repeat ultrasound examinations between five and 12 weeks' gestation. First-trimester bleeding was the only clinical sign of this phenomenon. Postpartum evidence of the vanishing twin phenomenon was found in five cases. Morphologically, the lesions were characterized by well-delineated plaques of perivillous fibrin deposition, associated in one case with embryonic remnants. This focal degenerative change of the placental mass, which also exists in about 25% of placentas from uncomplicated term pregnancies, may be the only clue to the disappearance of one conceptus.

Female↗
PubMed1988

[The significance of C-reactive protein in the diagnosis of chorioamnionitis in cases of premature rupture of the membranes].

We have retrospectively studied the changes in the level of C-reactive protein (CRP) and of white blood cells in 82 patients who had premature rupture of the membranes between the 20th and the 36th week of pregnancy in order to estimate the possibility of prenatal screening for amnion infections in early rupture of the membranes. The level of CRP was shown to be quickly and significantly raised in cases of clinical or histological chorioamnionitis, whereas the change in maternal leucocytes alters little and later. The level of CRP can be worked out as an early biological marker which is sensitive and cheap in the clinical supervision of cases with early rupture of the membranes.

C-Reactive Protein↗
PubMed1987

Morphological anomalies in the placentae of IVF pregnancies: preliminary report of a multicentric study.

Macroscopic characteristics of 100 fetal adnexae from pregnancies obtained by in-vitro fertilization and embryo transfer (IVF-ET) were compared with data for normal pregnancies taken from the literature. Material was obtained from 63 singleton, 15 twin, one triplet and one quadruplet pregnancies. The fetal and placental weights as well as the fetal:placental weight ratio were within the normal range for gestational age. Whilst placental morphology was normal, the insertion of the umbilical cord was frequently abnormal. Marginal (15%) and velamentous (14%) insertions of the umbilical cord were found more frequently than in a general obstetrical population (6% and 1% respectively). Excluding placentae from multiple pregnancies (which are known to have a higher incidence of abnormal cord insertion) the frequency did not decrease and remained significantly higher than in a normal population (P less than 0.01 and P less than 0.001, for marginal and velamentous insertion respectively). Abnormal insertion of the cord is of major clinical importance because of its association with vasa praevia and fetal haemorrhage (Benkiser Syndrome). Since this condition is thought to be caused by disturbed orientation of the blastocyst at implantation it is probably related to the IVF-ET procedure.

Embryo Implantation↗
PubMed1987

[376 amniocenteses performed under continuous ultrasonic control].

The authors report 376 amniocenteses carried out early and late in pregnancy under real time ultrasound at the University Clinic of St Pierre. The ability to watch the needle during the whole procedure of puncture makes it possible, as compared with amniocentesis that has been carried out without ultrasound or without real time ultrasound, to lessen significantly: perinatal mortality (0.26%), several attempts (0.9%) and the risk of accidental haemorrhage (1.6%). Particularly diminished are risks when it would be inevitable to have to put the needle through the placenta (31% of cases). The number of spontaneous abortions linked to the technique has virtually disappeared. When the operator has become very experienced in carrying out amniocentesis under real time ultrasound he becomes much more able to carry out other antenatal diagnostic procedures. Even when for certain indications amniocentesis is replaced by chorion villus biopsy in the first trimester or cord puncture in the third trimester, real-time ultrasound makes it less risky to carry out the procedures and the technique becomes a very useful one in the armamentarium of antenatal diagnostic methods.

Adult↗
PubMed1986

[Echographic evaluation of non-immunologic feto-placental anasarca. A series of 24 cases].

24 cases of non-immune feto-placental hydrops which were diagnosed by ultrasonography are presented. The precise etiology was possible in 21 of the cases using chromosome analyses, radiological assessments and carefully conducted post mortem examinations. The cause was maternal in 3 cases and due to fetal pathology in 18 cases, of which 5 were due to chromosome abnormalities. Three recessive autosomal syndrome, 9 malformations and in particular cardiac malformations and one twin pregnancy with transfusion from one fetus to the other were diagnosed. These features, which can be compared with those already in the literature, show that most of these cases of hydrops are due to genetic fetal defects and demonstrate how important it is to carry out chromosome analyses and systematic anatomo-pathological investigations. The results of these tests will indicate the way the doctors should look after the mother during pregnancy and how to deliver these mothers in subsequent pregnancies.

Adolescent↗
PubMed1984

Lethal multiple pterygium syndrome.

We report on two fetuses with a lethal form of multiple-pterygium syndrome born to first cousins. The two pregnancies aborted spontaneously in the 2nd trimester, the fetuses, 10-11 weeks of embryonic age, showing multiple pterygia and multiple cartilaginous fusions. One had cleft lip and palate. In both cases the microscopic anatomy of the placenta showed villi with scalloped border and intravillous trophoblastic invaginations.

Abnormalities, Multiple↗
PubMed1983

[Study of the endometrium following voluntary interruption of pregnancy in relation to the contraceptive method used following abortion].

A study of endometrial biopsies that was carried out around the 21st day after abortions in 424 patients who had had therapeutic terminations showed the effects of giving a sequential type of oral contraceptive immediately after the abortion had been carried out. This did not increase the rate of regeneration nor the proliferation of the endometrium and did not alter the local inflammatory reactions. It did, however, make it more difficult to eliminate decidua that had been retained as well as trophoblastic and villous structures and made it more likely that the classical appearance of the endometrium following pregnancy would be maintained.

Abortion, Therapeutic↗
PubMed1979

Hypospadias: a review.

Hypospadias is a common congenital anomaly with a prevalence estimated to be as high as 1 in 125 live male births. Its etiology is not entirely resolved but is embryologic in origin and has been attributed to fusion defects. Several authors believe it is a manifestation of intersex. Experience to date has produced a general consensus with regard to indications, timing and surgical principles for repair of the hypospadiac meatus. While two-stage procedures have been the mainstay of therapy, successful single-stage procedures have recently been developed. The prevention and management of the complications of persistant chordee, fistula and stricture make hypospadias repair one of the more challenging urologic procedures.

Age Factors↗
PubMed1979

Androgen receptors in benign and malignant prostatic tissue.

A new procedure has been developed to purify prostatic cell nuclei and to achieve a high yield of nuclear material for study. This technique allowed the investigation of the enzyme 5-alpha-reductase and its relationship to the translocation of dihydrotestosterone and androgen receptors into the nucleus of the prostatic cell. The studies revealed that 5-alpha-reductase was localized chiefly to the stromal components of all types of prostatic tissue. Although there is a higher concentration of dihydrotestosterone in carcinoma tissue the 5-alpha-reductase activity is low. Studies on the effect of androgens and antiandrogens on nuclear uptake of androgen revealed that androgens are potent stimulants of receptor translocation, while antiandrogens stimulate little or no translocation.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗