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Biomedical subjects

J C Morrison

Publications and source records attributed to J C Morrison.

At least 307 records · Page 17Linked to original sources
PubMed1984

Treatment of premature rupture of the membranes.

Few topics in obstetrics are debated more widely than the treatment of premature rupture of the fetal membranes (PROM). Over a two-year period, a retrospective analysis of 422 patients with that diagnosis revealed 86 mother-infant pairs at less than 37 weeks of gestation acceptable for review as it pertained to expectant or conservative management. The gestational age in these patients ranged from 26 to 36 weeks, with a mean of 31.9. Using the conservative management approach, 12% of the patients developed amnionitis during the antepartum period, and febrile morbidity was noted postpartum in eight patients. The neonatal outcome revealed a 14% incidence of respiratory distress syndrome (RDS). There were 18 infants with suspected sepsis, but of the 6 cases of proven infection, only 1 was related to amnionitis. Ten of the 12 infants contracting RDS were males, reflecting a reversal of the sex ratio found in those who did not develop RDS. The sex difference in the offspring was found to favor females with respect to RDS, even greater than 48 hours after rupture of the membranes. These data demonstrate that with the use of expectant management in patients with PROM at 26-36 weeks of gestation, there was no dramatic increase in maternal or neonatal infections.

Delivery, Obstetric↗
PubMed1984

Saturated phospholipids in amniotic fluid of normal and diabetic pregnancies.

To assess fetal lung maturation in normal and diabetic pregnancies, the authors studied two phospholipids that are more specific for pulmonary surfactant than total phosphatidylcholine (lecithin), namely saturated phosphatidylcholine and phosphatidylglycerol. Results indicated that saturated phosphatidylcholine concentrations normally increase from 10 to 20 nmol/mL before 34 weeks to as high as 150 nmol/mL at term. Although the absolute concentration of saturated phosphatidylcholine could not be used to reliably identify pregnancies leading to respiratory distress syndrome, a saturated phosphatidylcholine level greater than 50% of total phosphatidylcholine was associated with satisfactory neonatal pulmonary function, whereas RDS often occurred in premature infants when less than half the phosphatidylcholine was saturated. Carefully regulated diabetic pregnancies at 36 to 42 weeks of gestation were not different from matched control subjects with respect to total phosphatidylcholine, its ratio to sphingomyelin, saturated phosphatidylcholine, or phosphatidylglycerol. Respiratory distress syndrome did not occur in any infant of the 40 diabetic mothers studied, nor were there any congenital anomalies or cases of symptomatic hypoglycemia.

Amniotic Fluid↗
PubMed1983

Ontogeny of human fetal plasma progesterone, deoxycorticosterone, and deoxycorticosterone sulfate.

The concentrations of progesterone, deoxycorticosterone (DOC), and deoxycorticosterone sulfate (DOC-SO4) were determined in mixed umbilical cord plasma of abortuses and newborn infants delivered between 18 and 42 weeks' gestation. A wide range of values among individual samples was found for progesterone (224 to 2,152 ng/ml), DOC (1.6 to 10.4 ng/ml), and DOC-SO4 (17 to 154 ng/ml). Levels of progesterone and DOC in mixed umbilical cord plasma were not correlated; those of DOC and DOC-SO4 were positively correlated significantly (r = 0.3945, P less than 0.001). Whereas the mean plasma levels of DOC were similar throughout gestation, significant variation, as a function of gestational age, was found for progesterone and DOC-SO4, with levels of these steroids generally being higher near term than earlier in gestation. The administration of glucocorticosteroids to the mother resulted in a significant decrease (p less than 0.001) in plasma concentrations of DOC and DOC-SO4 in the newborn infant; levels of progesterone in umbilical cord plasma were not affected by maternal glucocorticosteroid treatment. These results suggest that the fetal adrenal glands play a direct, or possibly an indirect, role in the production of the DOC and DOC-SO4 that is present in the fetal compartment. In addition, since fetal plasma levels of progesterone are quite high throughout gestation, the potential exists for circulating progesterone to serve as a precursor for adrenal and extra-adrenal production of DOC and DOC-SO4.

Desoxycorticosterone↗
PubMed1983

Vaginal delivery following previous cesarean birth.

Because of the rising cesarean birth rate in the United States, renewed interest in vaginal delivery after prior abdominal operation has been evident. In a prospective collaborative study 789 patients were evaluated for inclusion into this investigation. Of the 717 subjects who entered the study 162 chose to attempt vaginal birth and 101 were successful. Desire for tubal sterilization and the lack of prior vaginal delivery were significant correlates of the group selecting repeat abdominal birth and of those who were unsuccessful when vaginal delivery was attempted. There were eight dehiscences and three uterine ruptures among the 717 patients and none was related to catastrophic outcome for the mother or neonate. Perinatal losses (12) were not related to uterine rupture or method of delivery. There were no significant differences in uterine disruption between patients selecting either route of delivery. Likewise ancillary factors such as a prior febrile puerperium (endometritis), number of prior cesarean births, low-vertical uterine incisions, recurrent operative indications, the use of epidural anesthesia, or oxytocin administration were not discriminating factors in whether women chose to attempt or were successful in completing vaginal delivery after prior abdominal birth. From our data vaginal birth after cesarean section appears to be safe if conducted in a carefully selected population that is closely monitored in a prospective manner.

Cesarean Section↗
PubMed1983

Quantified scoring of the amniotic fluid surfactant foam test and assessment of factors contributing to false negative test results.

Surfactant foam test scores were quantified by measuring the percent ring (%R) of foam produced at the meniscus of the 1:1 dilution tube. A comparison of %R scoring with conventional negative-positive rating of the foam test indicated that the %R value provided a more accurate estimate of the lecithin/sphingomyelin ratio. Based on clinical assessment of the newborn infant, the %R score also reduced the incidence of false negative test results by 47%. Variations in the assay ethanol fraction or tube size, as well as low amniotic fluid lecithin concentrations, were found to be potential determinants of false negative foam test results. The incidence of these false negative findings can be reduced by use of a %R score that has been empirically calibrated against neonatal outcome.

Amniotic Fluid↗
PubMed1983

Amniotic fluid phospholipids after maternal administration of dexamethasone.

The administration of corticosteroids to pregnant women in premature labor can accelerate fetal lung development and potentially prevent neonatal respiratory distress syndrome (RDS). Controversy exists, however, as to whether amniotic fluid phospholipid indices of lung maturation are influenced by such treatment. Without a suitable test for evaluating the fetal response to corticosteroids, there is no method of recognizing whether and when lung development has been stimulated. In an attempt to resolve this issue, we carried out a study of amniotic fluid phospholipids as part of the National Institutes of Health multicenter trial of prenatal corticosteroids. Amniocenteses were performed before the administration of either steroid hormone or placebo and approximately 1 week after a series of four injections was initiated. Analysis of the ratio of lecithin (phosphatidylcholine) to sphingomyelin (L/S ratio) revealed nearly identical values initially and no significant difference in the posttreatment means when 25 steroid-treated pregnancies were compared to 20 control pregnancies. Although there were significant increases in both groups during the interval between amniocenteses, no statistical difference was found in the extent of change in L/S ratios between the two groups, when pretreatment values were compared with those obtained an average of 1 week later. In addition to evaluating L/S ratios, we performed an assessment of phospholipid concentrations in 17 pregnancies before and after administration of dexamethasone. This revealed no detectable phosphatidylglycerol. There were increases in the absolute concentrations of phosphatidylcholine and disaturated phosphatidylcholine, but these changes were relatively modest in magnitude and could be attributable to either advanced gestational age or dexamethasone. Our results demonstrate that current tests of fetal lung maturity do not provide a routine means for prenatal detection of pulmonary maturational responses to corticosteroids.

Amniotic Fluid↗
PubMed1983

Descemet's membrane in penetrating keratoplasties of the human eye.

The response of Descemet's membrane in penetrating keratoplasty wounds was studied by light microscopy in 23 human eyes. Although only parts of the grafted areas could be sectioned in each eye, 15 splittings, full-thickness flanges, or fragmentations of Descemet's membrane were found in ten specimens. Seven of these abnormalities resulted in incarceration of Descemet's membrane into the wound. Malapposition of the wound edges was a causative factor in two additional eyes. Six of these incarcerations produced a visible stromal wound defect. Exacting surgical apposition of the stromal edges of the graft and recipient cornea can therefore be expected to reduce, but not eliminate, these healing abnormalities. Great care must be taken in cutting the graft and removing the recipient tissue to avoid stripping the tough Descemet's membrane from the overlying softer stroma with dull instruments or overlapping cuts.

Corneal Diseases↗
PubMed1983

Anterior collateral circulation in the primate eye.

Sequential microdissection and scanning electron microscopy of whole primate ocular lumenal methyl methacrylate corrosion castings were performed to determine the anatomic basis of collateral arterial blood flow to the anterior uvea. Collateral anastomoses were observed at three sites: (1) the episclera where the anterior ciliary arteries interconnect at the limbus to form the episcleral circle; (2) the ciliary muscle where anastomoses between the perforating anterior ciliary and long posterior ciliary arteries comprise the intramuscular circle, the most extensive of the three collateral arterial rings, and (3) the root of the iris where circumferentially oriented vessels derived from the intramuscular circle form the "major arterial circle". Of these, the "major arterial circle" is the most discontinuous. This multilevel collateral system probably accounts for the rarity of anterior segment ischemia following all but the most extensive extraocular muscle surgeries.

Anatomy↗
PubMed1983

Comparative efficacy of ibuprofen, indomethacin, and placebo in the treatment of primary dysmenorrhea.

Forty-two women with primary dysmenorrhea were successfully enrolled in a double-blind, three-way crossover study in which each patient received either ibuprofen (Motrin), indomethacin (Indocin), or a placebo during each of three successive painful menstrual cycles. Thirty-one patients successfully completed the study. The results showed that ibuprofen and indomethacin were superior to the placebo in their ability to relieve pain and that patients preferred ibuprofen to indomethacin. Ibuprofen was significantly superior to the placebo regarding the number of patients who could pursue normal daily function, whereas indomethacin was not. Four patients reported side effects, all during the indomethacin cycle.

Adolescent↗
PubMed1983

Fetal health assessment in pregnancies complicated by sickle hemoglobinopathies.

The contraction stress test (CST) and nonstress test (NST) are used as fetal health assessments. Severe sickle hemoglobinopathies in the parturient have been shown to place the fetus significantly at risk. This study correlates these fetal health assessment tests with outcome data in 58 pregnancies occurring in women with sickle cell disease. There were 30 patients with homozygous sickle cell anemia (HbS-S), 19 with hemoglobin S-C disease (HbS-C), and nine with hemoglobin S-thalassemia (HbS-Thal). All received prophylactic partial exchange transfusions as part of their antepartal care. At 34 weeks' gestation, NSTs followed by CSTs were begun in each patient. A total of 255 tests were performed. Of these, 19 NSTs and 24 CSTs were unsatisfactory or questionably abnormal and were repeated. There were no nonreactive NSTs, and no patient demonstrated a positive CST. The neonatal outcome revealed one infant who was small for gestational age and two infants who were of low birth weight but appropriate for gestational age. All infants survived and were normal. These data suggest that the fetal reactivity and placental reserve among these parturients with severe sickle hemoglobinopathies were uncompromised, as these tests have been shown to be relatively sensitive assessments of fetal well-being in other maternal disorders.

Anemia, Sickle Cell↗
PubMed1982

Bowman's layer in penetrating keratoplasties of the human eye.

Light microscopy disclosed ten examples of Bowman's layer incarcerations into the stromal wound in nine of 23 penetrating keratoplasty globes obtained either after death or by enucleation. Two cases involved separation of Bowman's layer from the underlying stroma. In the others, this layer remained attached to its stroma, and incarceration resulted from either fragmentation or malapposition of wound edges. Six of the incarcerations produced wound defects, and, of these three were associated with epithelial growth into the wound. These properties of Bowman's layer must be considered in the repair of corneal lacerations as well as in the performance of penetrating keratoplasties and epikeratophakia.

Cornea↗
PubMed1982

Full-thickness lamellar keratoplasty. A histologic study in human eyes.

Four human eyes, obtained 38 days to 5 years after full-thickness lamellar keratoplasty, were studied by light microscopy for evidence of fibroblast proliferation and collagen formation between the donor Descemet's membrane and the recipient stromal bed. There was delayed healing in the membrane to stroma interface, but at the graft margins a relatively normal stroma-to-stroma healing response was evident. Even in the five-year specimen, bridging of recipient collagen to donor Descemet's membrane was noted only where it was associated with subgraft vascularization. All donor endothelium had disappeared. These studies indicate that in human eyes, retention of Descemet's membrane results in a weaker total graft-host bond than provided by conventional lamellar keratoplasty. In addition, this altered healing may predispose to pseudoanterior chambers that may decrease visual acuity and diminish the theoretical optical advantages of a smooth Descemet's membrane in the graft host interface.

Adolescent↗