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Biomedical subjects

C J Lockwood

Publications and source records attributed to C J Lockwood.

138 records · Page 8Linked to original sources
PubMed1988

Sonographic assessment of the distal femoral and proximal tibial ossification centers in the prediction of pulmonic maturity in normal women and women with diabetes.

A noninvasive method for the assessment of fetal pulmonic maturity via the sonographic characterization of fetal distal femoral and proximal tibial epiphyseal ossification centers was evaluated. The study population included 82 patients in the third trimester of pregnancy, 47 of whom had uncomplicated gestations, while 35 had insulin-dependent diabetes. In uncomplicated pregnancies a distal femoral epiphysis measuring greater than or equal to 3 mm in the axial plane or the sonographic identification of a proximal tibial epiphysis of any dimension correlated with pulmonic maturity. The combination of a distal femoral epiphysis greater than or equal to 3 mm and the presence of a proximal tibial epiphysis was highly correlated with a lecithin/sphingomyelin ratio greater than or equal to 2:1 (sensitivity 100%, specificity 63%, negative predictive value 100%, and false-negative rate 0%). The Kappa value (K) for testing the agreement between ultrasound results and amniocentesis results was 0.39 (p less than 0.002). In diabetic pregnancies neither a distal femoral epiphysis greater than or equal to 3 mm nor a proximal tibial epiphysis of any dimension correlated precisely with the presence of phosphatidyl glycerol in the amniotic fluid. However, the combination of a distal femoral epiphysis greater than or equal to 3 mm and a proximal tibial epiphysis greater than or equal to 2 mm improved the prediction of phosphatidyl glycerol (sensitivity 83%, specificity 79%, negative predictive value 96%, false-negative rate 17%). The K value in this instance was 0.36 (p greater than or equal to 0.19). It is concluded that the sonographic assessment of the distal femoral and proximal tibial epiphyses and their dimensions in the axial plane may be useful as markers for pulmonic maturity in uncomplicated pregnancies.

Epiphyses↗
PubMed1988

Sonographic diagnosis of a pregnancy with a diffuse hydatidiform mole and coexistent 46,XX fetus: a case report.

Placental molar change with a coexistent live fetus is an unusual entity, particularly when diagnosed in the second trimester of pregnancy. In this case report, the sonographic findings of an abnormally enlarged, diffuse molar placenta with a normal living fetus in the second trimester prompted karyotype analysis. Although triploidy was anticipated, a normal 46,XX chromosomal complement was identified. Histopathology of the placenta after delivery confirmed the rare syndrome of diploid partial mole. Antenatal management of this unusual pregnancy complication is addressed.

Adult↗
PubMed1988

Sonographic assessment of the fetal frontal lobe: a potential tool for prenatal diagnosis of microcephaly.

A prospective ultrasound evaluation of 150 normal pregnant women was conducted between 15 and 40 weeks' gestation. A variety of biometric measurements were obtained that included measurements of the frontal lobe distance (the anterior edge of the frontal horns of the lateral ventricles to the frontal bone) and the thalamic frontal lobe distance (measured from the posterior edge of the thalami to the frontal bone). Analysis of these data revealed a high degree of correlation between the gestational age and the frontal lobe distance (R2 = 0.89, p less than 0.0001), and between the gestational age and thalamic frontal lobe distance (R2 = 0.93, p less than 0.0001). Similarly, a high degree of correlation was also found between the biparietal diameter and the frontal lobe distance (R2 = 0.95; p less than 0.0001), between the biparietal diameter and the thalamic frontal lobe distance (R2 = 0.90, p less than 0.0001), and between the frontal lobe distance and the thalamic frontal lobe distance (R2 = 0.92, p less than 0.0001). The relationships between femur length and frontal lobe distance (R2 = 0.89, p less than 0.0001) and between the femur length and the thalamic frontal lobe distance (R2 = 0.945, p less than 0.0001) were also evaluated. Nomograms for the relationships between gestational age and frontal lobe distance and thalamic frontal lobe distance were generated and included the mean +/- SD and the percentile distributions. Growth of the frontal lobe was best described by a first-degree linear equation. The results of this study demonstrate the pattern of growth of the frontal lobe and the high rate of correlation between growth of the frontal lobe and the gestational age and the biparietal diameter. These findings offer a potential method by which the decreasing size of the frontal lobe, as shown in three cases described herein, can be evaluated prenatally and thus serve as a useful tool in the prenatal diagnosis of microcephaly.

Female↗
PubMed1987

Intrinsic intrathoracic malformations of the fetus: sonographic detection and clinical presentation.

Intrinsic intrathoracic malformations are a rare group of congenital anomalies associated with high fetal and neonatal mortality rates. The antenatal sonographic appearance and the adequacy of diagnosis in 15 affected fetuses were evaluated. An accurate prenatal diagnosis was made in 12 cases; the precise nature of the intrathoracic defect was incorrectly categorized in two fetuses, and the defect was missed entirely in one affected fetus. Antenatal detection and characterization of intrinsic intrathoracic congenital malformations seems possible, but requires a high index of suspicion, familiarity with their sonographic appearances, and meticulous attention to detail.

Bronchogenic Cyst↗
PubMed1986

Assessment of fetal growth.

Normal fetal growth is a logarithmic process, marked by rapid mitosis at its early stages and by cellular hypertrophy and the accumulation of fat, glycogen, and connective tissue later in gestation. Growth-retarding influences can alter cell number, with a symmetric pattern of IUGR resulting if they occur early. Later insults, the result of uteroplacental compromise, affect cell size and may cause an asymmetric growth retardation. Fetuses with asymmetric growth retardation are at particular risk for intrauterine fetal demise and fetal distress in labor. The assessment of fetal growth is complicated by a lack of clear definition for what constitutes normality. Fetal growth curves should be derived from uncomplicated pregnancies. Separate curves should be available on the basis of multiple gestation and sex, maternal parity, and ethnic-racial grouping. Correction factors for maternal height and prepregnancy weight as well as sibling size at birth would be useful. Birth weight-derived data are suspect for preterm gestations; sonographic fetal weight curves may improve accuracy. Without sensitive epidemiologic growth assessment, other modalities (clinical, biochemical, and sonographic) will have limited usefulness. The assessment of fetal growth may include clinical means but care must be taken to garner a meticulous history and to record precisely serial fundal height. Many biochemical methods have been proposed for the detection of IUGR but they have a limited role as screening tests. Ultrasound remains the best method for the diagnosis, characterization, and follow-up of IUGR. Ultrasonography allows for the precise estimation of fetal weight. The calculation of HC:AC ratios allows for characterization of the pattern of IUGR. Evaluation of amniotic fluid volume and placental grading as well as the search for congenital anomalies are helpful exercises. Doppler flow studies of uterine and fetal blood flow may provide an understanding of the cause and severity of the growth-retarding process. Finally, careful antenatal surveillance and judicious timing of delivery are required following the identification of IUGR. Delivery should be planned in concert with the neonatologist.

Biometry↗
PubMedDate not supplied

von Willebrand disease and pregnancy.

von Willebrand Disease (vWD) affects approximately 1% of Americans and as many as 25% of women referred for evaluation of menorrhagia. We briefly review the history of vWD, its molecular defects, and diagnostic criteria for each subtype of disease. We also address obstetric management of the patient with vWD. While there is a significant increased risk for postpartum hemorrhage, patients with vWD should not be discouraged to undertake pregnancy.

Female↗
PubMedDate not supplied

Prophylactic and emergent arterial catheterization for selective embolization in obstetric hemorrhage.

Treatment of obstetric hemorrhage by the selective embolization of damaged pelvic vessels under fluoroscopy holds promise as an alternative to surgical intervention. Unfortunately, the effectiveness of selective embolization is often compromised by its use in emergent settings following the failure of primary operative approaches. Therefore we compared the efficacy of prophylactic versus emergent catheter placement for selective embolization in nine patients with or at risk for obstetric hemorrhage. In four patients with acute obstetric hemorrhage catheterization and embolization was carried out following the failure of initial medical and surgical approaches. In five patients determined to be at risk for intrapartum hemorrhage based on sonographic findings, catheters were inserted into the hypogastric vessels prior to elective cesarean delivery. Three of these five patients subsequently required selective embolization. In comparison to patients undergoing selective embolization following prophylactic catheter placement, patients in the emergent group all had a coagulopathy at the time of embolization, sustained substantially greater blood loss, and had an increased rate of postpartum complications. Finally, there was a significant reduction in total embolization time and therefore in radiation exposure in patients undergoing prophylactic catheter placement prior to selective embolization. These data support the conclusion that in patients determined to be at risk for intrapartum or postpartum hemorrhage the prophylactic placement of catheters allows for selective embolization in a hemodynamically intact patient with stable coagulation indices, theoretically reducing the risk of maternal morbidity and possibly mortality.

Adult↗
PubMedDate not supplied

A biological model for the regulation of peri-implantational hemostasis and menstruation.

OBJECTIVE: To delineate the physiologic mechanisms whereby the human endometrium maintains hemostasis during endovascular trophoblast invasion but permits menstrual hemorrhage. METHODS: Experimental results are presented that are relevant to developing a comprehensive biological model for studying peri-implantational hemostasis and menstruation. RESULTS: A marked increase in the expression of tissue factor (TF) and type-1 plasminogen activator inhibitor (PAI-1) and an inhibition of tissue-type and urokinase-type plasminogen activators (tPA and uPA, respectively), matrix metalloproteinases (MMP), and endothelin-1 (ET-1) expression accompany progestin-induced decidualization of estrogen-primed endometrial stromal cells both in vivo and in vitro. The presence of these important regulators of hemostasis, fibrinolysis, extracellular matrix (ECM) turnover, and vascular tone in decidualized human stromal cells and decidual cells isolated from gestational endometrium suggests a mechanism to explain the absence of hemorrhage during invasion of the endometrial vasculature by trophoblasts. Conversely, progesterone withdrawal reduces TF and PAI-1 expression and increases tPA, uPA, MMP, and ET-1 expression accounting for the hemorrhage, enhanced fibrinolysis, ECM degradation, and ischemic spiral arterial vascular injury characterizing menstruation. CONCLUSION: Perivascular decidualized endometrial stromal cells are spatially and temporally positioned to promote endometrial hemostasis during implantation but, paradoxically, promote the hemorrhage of menstruation via their hormone-regulated expression of hemostatic, proteolytic, and vasoactive proteins.

Embryo Implantation↗