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Biomedical subjects

J C Morrison

Publications and source records attributed to J C Morrison.

At least 271 records · Page 15Linked to original sources
PubMed1987

Third-trimester biparietal diameter as a predictor of fetal lung maturity.

The major fetal risk associated with elective delivery is unexpected fetal lung immaturity and the development of hyaline membrane disease soon after birth. Prior to elective vaginal or abdominal delivery it has become standard obstetric practice to predict fetal lung maturity by the analysis of amniotic fluid obtained by amniocentesis or vaginal pool sample following preterm rupture of membranes. A correlation between third-trimester fetal biparietal diameter and the lecithin/sphingomyelin (L/S) ratio has been established by several investigators. In order to determine if a threshold BPD could be consistently correlated with fetal lung maturity, we retrospectively examined the hospital and laboratory records of a group of 115 nondiabetic parturients in whom BPD measurements and amniotic fluid analysis for L/S ratio had been performed for various clinical indications. A threshold BPD of greater than or equal to 9.2 cm in all parturients who underwent elective repeat cesarean delivery was associated with no hyaline membrane disease (HMD). Two of the three neonates who developed HMD had mature L/S ratios but were products of pregnancies complicated by third-trimester hemorrhage. A review of our present data suggests that about one-third of clinically-indicated amniocenteses in the absence of maternal diabetes or third-trimester hemorrhage could potentially be avoided without adverse neonatal impact. Possible therapeutic application of this finding requires further prospective study.

Amniotic Fluid↗
PubMed1987

Dynamic Relation between Expansion and Cellular Turgor in Growing Grape (Vitis vinifera L.) Leaves.

Measurements of the growth and water relations of expanding grape (Vitis vinifera L.) leaves have been used to determine the relationship between leaf expansion rate and leaf cell turgor. Direct measurement of turgor on the small (approximately 15 micrometer diameter) epidermal cells over the midvein of expanding grape leaves was made possible by improvements in the pressure probe technique. Leaf expansion rate and leaf water status were perturbed by environmentally induced changes in plant transpiration. After establishing a steady state growth rate, a step decrease in plant transpiration resulted in a rapid and large increase in leaf cell turgor (0.25 megapascal in 5 minutes), and leaf expansion rate. Subsequently, leaf expansion rate returned to the original steady state rate with no change in cell turgor. These results indicate that the expansion rate of leaves may not be strongly related to the turgor of the leaf cells, and that substantial control of leaf expansion rate, despite changes in turgor, may be part of normal plant function. It is suggested that a strictly physical interpretation of the parameters most commonly used to describe the relationship between turgor and growth in plant cells (cell wall extensibility and yield threshold) may be inappropriate when considering the process of plant cell expansion.

Journal Article↗
PubMed1987

The effects of dexamethasone and anencephaly on newborn serum levels of apolipoprotein A-1.

Since the control of production and clearance of plasma lipoproteins in utero is largely unknown, we sought to evaluate the effects of glucocorticosteroid (dexamethasone) treatment of developing fetuses and of chronic intrauterine hypercholesterolemia, due to fetal anencephaly, on newborn serum levels of apolipoprotein A-1 (Apo A-1), the major apoprotein of high density lipoproteins (HDL). Among preterm newborn infants (26-32 weeks gestation), the total, HDL, and low density lipoprotein cholesterol levels in umbilical cord serum of 11 newborns exposed to 4 doses of dexamethasone (5 mg each) within 1 week of delivery [mean, 3.05 +/- 1.01 (+/- SD), 0.83 +/- 0.18, and 1.84 +/- 0.69 mmol/L, respectively] and of 3 anencephalic newborns (2.84 +/- 0.57, 0.83 +/- 0.36, and 1.89 +/- 0.54 mmol/L) were increased to a similar extent over those in 17 normal newborns (1.76 +/- 0.16, 0.62 +/- 0.16, and 1.14 +/- 0.13 mmol/L). On the other hand, umbilical cord serum Apo A-1 levels were markedly increased only in the dexamethasone-treated preterm newborns (1.35 +/- 0.55 g/L; anencephalic, 0.78 +/- 0.15 g/L; normal, 0.68 +/- 0.06 g/L). Also, whereas serum total, HDL, and low density lipoprotein cholesterol levels in 5 term anencephalic newborns (3.85 +/- 1.37, 1.06 +/- 0.08, and 2.64 +/- 0.91 mmol/L) were substantially higher than those in 41 normal term newborns (1.42 +/- 0.28, 0.57 +/- 0.12, and 0.74 +/- 0.05 mmol/L), serum Apo A-1 levels were similar at term in anencephalic (1.01 +/- 0.30 g/L) and normal newborns (0.99 +/- 0.08 g/L). Normal Apo A-1 and lipoprotein cholesterol levels were found in an additional newborn who was delivered 30 days after exposure to dexamethasone. We conclude that intrauterine glucocorticosteroid treatment leads to transiently increased serum Apo A-1 levels in the newborn. This increase, however, is not likely to be secondary consequence of the hypercholesterolemia that also occurs in such newborns, since hypercholesterolemia of a similar extent in anencephalic newborns, who have atrophic adrenals, was not associated with marked changes in serum Apo A-1 levels.

Anencephaly↗
PubMed1987

Regional microvascular anatomy of the rabbit ciliary body.

Vascular luminal castings of rabbit eyes were microdissected and studied with the scanning electron microscope to delineate the anatomy of the ciliary body microvasculature. We found regional microvascular differences corresponding to well known gross topographical and ultrastructural differences that may indicate regional functional specialization. The major arterial circle of the iris, derived solely from the long posterior ciliary arteries, supplies the ciliary body via two types of arterioles: anterior and posterior. Spiral iridial process capillaries arise from the anterior (iris) arterioles, are radially arranged along the back of the iris and drain directly into the iris veins. Arterioles from the posterior (ciliary) arterioles enter the head of the process, supplying its tortuous capillaries, some of which drain back into the iris veins. Other capillaries turn posteriorly to form relatively straight, parallel capillaries within the process leaf that drain into the choroidal system via marginal process veins. More posterior arterioles supply capillaries to the base of major processes, to the interprocess ciliary web, and to minor processes. The presence of a dual arteriolar supply to the ciliary processes has also been found in primates and suggests that the rabbit may represent a suitable animal model for the study of factors governing regional ciliary process perfusion.

Animals↗
PubMed1987

Comparative microvascular anatomy of mammalian ciliary processes.

Methylmethacrylate lumenal castings of the ciliary body microvasculature were prepared from eight mammalian species and studied with the scanning electron microscope. In all of these species, the ciliary body is supplied by the major arterial circle, which originates solely from the long posterior ciliary arteries without contribution from the anterior ciliary circulation. In contrast to primates and rabbits, the ciliary processes of the eight species we studied are supplied by only one type of arteriole, which travels posteriorly from the major arterial circle to the iris root, where it gives rise to ciliary process arterioles. Using precise microdissection techniques, we found marked interspecies variations in ciliary process angioarchitecture among the mammalian eyes examined. Rodents (rat and guinea pig) demonstrated several interesting similarities to primates, with extensive interprocess connections and irregularly dilated, concentrically parallel capillaries traveling posteriorly to empty into the choroidal veins. In addition, rat ciliary process arterioles displayed marked focal constrictions suggestive of precapillary "sphincter" agonal activity. The carnivore ciliary process (cat and dog) is supplied by a single arteriole traveling posteriorly throughout its length and sending capillary arcades to its margin from where they drain outward into venous sinuses at the base of the process. Ungulate processes (sheep, goat, pig and cow) receive blood from multiple arterioles that occupy the process core along with veins that empty into the choroidal circulation. These vessels serve delicate capillaries lying on the sides, margin and head of each process. The anatomic variations described here should be considered in the design and interpretation of physiologic and immunohistochemical studies of ciliary body vascular perfusion in non-primate animal models.

Animals↗
PubMed1986

Comparative study of flurbiprofen and morphine for postsurgical gynecologic pain.

This single-dose, double-blind, randomized, placebo-controlled study assessed the efficacy and safety of 50 mg of flurbiprofen (Ansaid, Upjohn) in the relief of postoperative pain following cesarean section, as well as vaginal or abdominal hysterectomies. Results show that both 50 mg of oral flurbiprofen and 10 mg of intramuscular morphine sulfate were significantly superior to placebo in 161 patients with respect to pain intensity after medication, pain relief scores, need for additional analgesia, and overall clinical evaluation of pain relief. By two hours after treatment, there were no significant differences between morphine sulfate and flurbiprofen in terms of pain intensity or degree of pain relief. According to investigators' global evaluations of efficacy, both active treatments were statistically superior to placebo. The only adverse reaction occurred in the morphine treatment group. Flurbiprofen administered orally for the relief of moderate to severe pain following major gynecologic surgery appears to be equal to morphine sulfate and superior to placebo in efficacy and safety. Unlike morphine, flurbiprofen is a nonparenteral, uncontrolled substance, and thus patient acceptance is improved while nursing time is decreased.

Adult↗
PubMed1986

External cephalic version of the breech presentation under tocolysis.

External cephalic version with tocolysis at or near term has been advocated to avoid cesarean birth for breech presentation. In our institution this maneuver was successfully performed in 207 of 304 parturients without major complications, and all but six had vertex presentation at delivery. The success of version was inversely correlated with gestational age but was not correlated with ease of version, number of attempts, or placental location. When this 3-year period was compared with the previous three years (1979 to 1981), there was a significant reduction in the number of breech presentations during labor, whereas the total delivery rate remained relatively constant over the 6-year period. It appears that in a carefully selected population, external version near term can be used safely to reduce the need for abdominal birth because of breech presentation.

Breech Presentation↗
PubMed1986

Correlation of neonatal acid-base status with Apgar scores and fetal heart rate tracings.

In this study the immediate neonatal acid-base status, obtained via a double-clamped segment of umbilical cord, in 75 term, singleton vaginal deliveries was compared to electronic fetal heart rate recordings and Apgar scores. Of 75 neonates, 59 had 1-minute Apgar scores greater than or equal to 7 and 52 had an initial pH greater than 7.20. Six of the 16 neonates with a 1-minute Apgar score less than 7 demonstrated a low pH (less than 7.20). At 5 minutes only eight of 75 neonates had Apgar scores less than 7 with six of the eight having pH values less than 7.20. Of those neonates with Apgar scores greater than or equal to 7 and pH less than 7.20 (seven neonates at 1 minute, two at 5 minutes), none had metabolic acidosis. Eighteen fetal heart rate tracings were considered abnormal; acidosis was confirmed in eight (44%) by pH criteria, yet only three of the eight neonates had low Apgar scores. Our investigations suggest that the combination of fetal heart rate monitoring, cord blood pH, and Apgar assessment is better than any one parameter alone as an evaluation of fetal status just after delivery.

Apgar Score↗
PubMed1986

Purification and characterization of B-protein from human serum.

B-Protein, present in the serum of individuals with cancer, has been purified to electrophoretic homogeneity. The purification procedure consisted of chromatography on Sephacryl S-200, Affi-Gel Blue, Con A--Sepharose 4B, wheat germ lectin--Sepharose and preparative polyacrylamide gel electrophoresis. The molecular weight of B-Protein is estimated to be 100 000 to 120 000. It is a glycoprotein which appears to be composed of two subunits, each with a molecular weight of approximately 52 000. Analytical polyacrylamide gel electrophoresis and analytical ultracentrifugation data indicate that purified B-Protein is homogeneous. Isoelectric focusing studies also show the purified B-Protein to be homogeneous in composition consisting of a single band of pI = 4.8. Amino acid analysis is consistent with this acidic isoelectric point. Other analyses indicate that B-Protein contains 7% carbohydrate and 7% lipid in the form of triglycerides.

Amino Acids↗
PubMed1986

Contraction stress test by nipple stimulation: efficacy and safety.

During a one-year period, 838 nonstress tests, 425 nipple stimulation contraction stress tests (NS-CSTs), and 115 spontaneous CSTs were done. Results were compared to those of NSTs and CSTs done by classic methods during a previous one-year period. The results revealed no hyperstimulation from contraction stress testing with nipple stimulation, and a significant reduction in the time to perform both tests conducted simultaneously when compared to the nonstress test plus classic oxytocin challenge test. The time to perform the combined tests compared to the routine nonstress test was not significantly different. Moreover, a cost-saving was also demonstrated. The combination of the NST and nipple stimulation CST appeared to be safe, efficacious, and cost-effective.

Breast↗
PubMed1986

Microanatomy and modulation of the ciliary vasculature.

Scanning electron microscopy of primate anterior uveal methylmethacrylate vascular casting has revealed a complex, multifaceted, highly anastomotic vasculature. The anterior and long posterior ciliary arteries interconnect to form three collateral vascular circles: the episcleral circle; the intramuscular circle; the 'major' arterial circle. Located at the iris root, the 'major' arterial circle is the most discontinuous with its circumferentially oriented vessels frequently ending in iris and ciliary process arterioles. The ciliary process microvasculature is also highly complex, with two types of arterioles: anterior and posterior. Anterior arterioles possess focal constrictions near their origins and supply capillaries to the anterior regions and margins of the major ciliary processes. Posterior arterioles are less constricted and supply the minor ciliary processes and the central portions of the major processes. These findings, and the demonstration of multiple other channels, suggest several mechanisms by which blood can be shunted between and around the major and minor ciliary processes. In addition, we illustrate the use of scanning electron microscopy of methacrylate luminal castings to demonstrate alterations of the ciliary microvasculature in response to both pharmacologic and surgical stimuli. Quantitative studies of methacrylate castings may allow future localisation of the sites of vasomotor substance activity and improve our understanding of the role of blood flow in aqueous humour production.

Animals↗
PubMed1986

Acute management of sickle cell crisis in pregnancy.

Vaso-occlusive sickle cell crisis (VSCC) is the most common maternal complication in pregnancies associated with sickle hemoglobinopathies. Maternal and fetal morbidity and mortality secondary to this serious obstetric problem can be reduced significantly with a well-devised therapeutic plan, expert perinatal teams, and careful attention to obstetric and medical detail in a setting of comprehensive tertiary health care. A variety of better medical, obstetric, and neonatal care practices have helped considerably to improve the combined life span for affected mothers and fetuses. In the absence of any effective and safe pharmacologic agent to prevent sickle crisis, our experience suggests that adherence to the described management principles offers the greatest hope to the sickling parturient that her vaso-occlusive crises can be effectively managed for a healthy outcome, both for herself and for her baby.

Anemia, Sickle Cell↗
PubMed1985

Antenatal therapy with corticosteroids and postpartum complications.

In a group of patients receiving dexamethasone antenataly, there was no difference in incidence of postpartum complications when compared to a group treated with a placebo. It is concluded that, from the maternal point of view, selected pregnant patients may safely receive corticosteroids to minimize the incidence of respiratory distress syndrome.

Dexamethasone↗
PubMed1985

Clinical amniotic fluid infection and its effect on the neonate.

This study was undertaken to determine the effects of clinical amniotic fluid infection on the neonate in terms of bacterial infection, hyaline membrane disease, asphyxia, and mortality. A retrospective chart review was made of 107 mothers with clinical amniotic fluid infection and their infants at this institution over a 3-year period. The next live-born infant with a birth weight within 100 gm and gestational age within 2 weeks was chosen as a control for each study patient. The rate of prematurity in the study group was 71%. When prematurity was controlled for, there was no significant difference in regard to asphyxia, hyaline membrane disease, bacterial sepsis, and death between the study and control groups. These findings suggest that the adverse outcome for infants delivered to mothers with clinical amniotic fluid infection at this institution was related primarily to their prematurity.

Apgar Score↗