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Biomedical subjects

J C Morrison

Publications and source records attributed to J C Morrison.

At least 199 records · Page 11Linked to original sources
PubMed1992

Hematologic disorders in pregnancy.

Hematologic disorders in pregnancy are relatively common and encompass a wide spectrum of clinical conditions. The treatment and obstetric management of the majority of these diseases are well established, although controversy exists in areas such as sickle cell disease and ITP. Once the diagnosis of a specific disorder is confirmed, therapy is directed toward improved perinatal outcome. Recent advances in prenatal diagnostic techniques make in utero diagnosis feasible for most of the inherited disorders and aid in genetic counseling.

Anemia↗
PubMed1992

Pathfinder direct fluorescent antigen test for diagnosing maternal chlamydial infections. An evaluation.

Chlamydia trachomatis is a frequent cause of genital infections in young women. Chlamydial infections may adversely affect perinatal outcome. We compared the Pathfinder direct fluorescent antigen (DFA) test for chlamydial infections to tissue culture isolation in an obstetric population. Among 984 samples, 152 (15.4%) were inadequate for evaluation using the Pathfinder DFA test. Among 783 evaluable specimen pairs, the sensitivity, specificity, and positive and negative predictive values of the Pathfinder, as compared to tissue culture isolation, were 25%, 97.5%, 32.1% and 96.4%, respectively. On the basis of that experience, we do not recommend the Pathfinder DFA test as a clinical screening device for detecting chlamydial infections complicating pregnancy.

Chlamydia Infections↗
PubMed1992

Intrapartum clinical, sonographic, and parous patients' estimates of newborn birth weight.

The accuracy of estimating birth weight clinically, sonographically (using femur length and abdominal circumference), and by maternal prediction was studied prospectively in 106 term parous women who were in active labor. Estimates of birth weight by these women had lower standardized error (86.8 +/- 78.0 g/kg) than either clinical estimates (90.2 +/- 84.8 g/kg) or sonographically derived estimates (155.8 +/- 118.0 g/kg) of birth weight (P = not significant). Maternal estimates of birth weight were within +/- 10% of the actual weight in 69.8%, compared with 66.1% for clinical estimates and 42.4% for sonography. A term parous woman in labor can predict the birth weight with accuracy comparable to a clinical estimation by a physician or a sonographic estimate based on infant measurements.

Adult↗
PubMed1992

Optic nerve head microvasculature of the rabbit eye.

Vascular luminal castings of rabbit eyes were microdissected and studied with scanning electron microscopy to elucidate the three-dimensional angioarchitecture of the optic nerve head. Using sequential microdissection, an incomplete arterial circle was identified as terminal branches of two to three short posterior ciliary arteries around the optic nerve head. Several recurrent branches from the arterial circle form a pial arterial network. This pial system supplies the optic nerve head microvasculature and receives numerous venules from them. The only large vessel to enter the optic nerve is a central retinal artery that has few branches within the optic nerve and provides several branches at the surface of the optic disc. Moderately numerous vessels connect the retinal and ciliary vascular layers within the optic nerve head. Few arterioles to the optic nerve head arise from the choroid; however, there are a small number of capillary and numerous venous connections between them. These results indicate that the principal blood supply of the rabbit optic nerve head is derived from the short posterior ciliary arteries by the arterial circle. The retinal arteries contribute to the surface vasculature of the optic nerve head. The pial system also plays a significant role in both supply and drainage of the rabbit optic nerve head.

Animals↗
PubMed1991

Use of continuous flow erythrocytapheresis in pregnant patients with sickle cell disease.

The role of partial prophylactic red cell exchange transfusion in the management of pregnant patients with major sickle hemoglobinopathies is unclear. Over a 10-year period, 131 pregnant patients with major hemoglobinopathies (HbS 101, HbS-C 30) were managed by the same group of physicians. Of these, 103 received partial prophylactic exchange transfusion early during prenatal care while 28 received blood only when serious complications developed (control group). Patients treated with exchange transfusion received continuous flow erythrocytapheresis on an outpatient basis. The results indicate that there were fewer crises (P = .0001), a reduction in other significant medical complications (P = .002), and a decrease in maternal hospital days (P = .05) in those receiving prophylactic transfusions compared to women in the control group. The number of preterm deliveries (P = .004), the prevalence of low birthweight infants (P = .01), and the perinatal death rate (P = .01) were significantly lower among those who were routinely transfused. Two patients developed hepatitis, five had transfusion reactions, and 11 were found to have alloantibodies among those receiving prophylactic transfusions versus one, two, and five patients, respectively, in the control group. The results indicate a benefit of this methodology in the treatment of pregnant sickle cell patients in our population. However, a national collaborative randomized study is needed to adequately address the controversy regarding the use of red cell exchange in the pregnant sickler.

Adolescent↗
PubMed1991

Effect of pregnancy on the accuracy of light-reflection rheography.

Light-reflection rheography is a noninvasive method to detect venous obstruction by indirectly measuring venous emptying time. In nonpregnant women it has greater than 90% sensitivity when compared with venography but has not been tested during gestation. To determine if the nonthrombotic occlusion of venous outflow by the pregnant uterus might alter the performance of light-reflection rheography, we examined 17 normal patients with a vascular Accuscan (Hemodynamics, Inc., Boca Raton, Fla.) in the third trimester of pregnancy and 11 patients during the early second trimester. These results were compared with the defined normal (nonpregnant) rate of venous emptying (slope 0.54 +/- 0.06). The mean (+/- SD) for the entire sample was 0.58 +/- 0.23 mm/sec in the right leg and 0.52 +/- 0.19 mm/sec in the left leg measured in the standard sitting position (p = 0.21). The results did not vary with gestational age. A subset of patients in late pregnancy were used to compare the effect of various positions (supine, lateral decubitus, and sitting) on test performance. Positions other than sitting provided results that were inconsistent. It appears that the large pregnant uterus does not significantly obstruct venous outflow from the lower extremities in the standard sitting position; thus the results of light-reflection rheography are not affected. Comparison of light-reflection rheography versus venography in pregnant patients with suspected venous thrombosis is being investigated.

Female↗
PubMed1991

Postpartum preeclampsia-induced shock and death: a report of three cases.

Three patients with preeclampsia died as a result of prolonged postpartum hypotension that was unrelated to blood loss. Autopsy failed to reveal a cause of death. The sudden onset of hypotensive shock within 24 hours of delivery occurred in all patients, with coexistent hyponatremia present in the two patients in whom it was evaluated. These three maternal deaths appear to have occurred as a result of the previously described entity of postpartum preeclamptic shock.

Adolescent↗
PubMed1991

Administration of heparin by subcutaneous infusion with a programmable pump.

Heparin has a short half-life (8 to 12 hours) and therefore must be administered by continuous infusion or by intermittent subcutaneous injection. Intermittent subcutaneous injection may lead to fluctuation in the levels of anticoagulation attained. In correcting this deficiency, the programmable automated subcutaneous infusion pump in conjunction with weekly home nursing visits has been used. Eight pregnant women with documented deep venous thrombosis or embolic events before pregnancy who received such therapy were studied. Eight similar subjects who received intermittent subcutaneous injection, matched for age, parity, site of deep venous thrombosis, and days on a regimen of heparin therapy, served as the control group. The mean daily dose of heparin by subcutaneous infusion pump was higher (29,445 vs 13,822 U), resulting in smoother, more therapeutic heparinization (mean partial thromboplastin time, 20.6 vs 10.4 seconds above control) when compared with the intermittent subcutaneous injection group (p less than 0.05, p less than 0.007). There were two complications (hematoma, site infection) in the intermittent subcutaneous injection group while none occurred in the subcutaneous infusion pump group. When used in concert with weekly home visits, the subcutaneous infusion pump method of administration allowed more even control of anticoagulation, appeared to result in fewer complications (although not statistically significant), and subjectively was better received by patients than the intermittent subcutaneous injection technique.

Adult↗
PubMed1991

Pharmacologic induction of fetal lung maturity.

The consequences of a preterm birth are usually not secondary to a developmental abnormality but rather due to the immaturity of one or more organ systems. Because neonatal RDS is the most common and the most severe complication of a preterm delivery, a major emphasis has been placed on its prevention and/or treatment. Despite intensive research efforts directed at preventing or inhibiting preterm labor, to date there is no universally effective method that can be used in most patients. As a result, preterm birth will continue to occur and continue to challenge the health care provider. Several medications and hormones have been shown to stimulate endogenous surfactant production in the fetus. Their administration to women at risk of delivering preterm can decrease both the incidence and severity of neonatal RDS. The primary limiting factor with most agents is the need to delay birth for 48 to 72 hours to achieve maximum therapeutic effect. This mandates the obstetric health care provider not only identify parturients who will deliver preterm but also manage their intrapartum course to achieve maximum value from these pharmacologic agents. Lastly, in those patients in whom labor can be neither inhibited nor safely delayed, exogenous surfactant therapy offers real hope particularly to the very low birth weight baby. To obtain maximum benefit in the very premature infant, i.e., less than 30 weeks' gestation, therapy ideally should begin immediately after birth and before the first breath. However, to offer such therapy, patients need to be identified during the intrapartum period.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1991

Pregnancy after Fontan repair of tricuspid atresia.

We have described a patient who had a cyanotic congenital heart disease (type Ib tricuspid atresia), with initial palliation accomplished in childhood via a Glenn procedure. In 1985, she had a Fontan repair with the Bjork modification; 3 years later she achieved her first pregnancy at age 27. Maternal Doppler echocardiography in early pregnancy showed good flow through the constructed conduit, with normal left ventricular size and function. Fetal echocardiography at 22 weeks' gestation via two-dimensional, M-mode, pulsed Doppler, and color flow mapping revealed no evidence of fetal cardiac disease. At 25 weeks' gestation recalcitrant preterm labor developed, and the infant was delivered spontaneously. Labor, delivery, and puerperium were uncomplicated, and the newborn (though too premature to survive) was of appropriate weight for gestational age, without evidence of congenital heart disease or other anomalies. We believe this is the first report of pregnancy and spontaneous delivery in a patient who has had Fontan repair of a congenital heart defect.

Adult↗
PubMed1991

Cordocentesis (funipuncture) by maternal-fetal fellows: the learning curve.

One hundred cordocenteses were attempted at the University of Mississippi Medical Center between July 1, 1989, and June 1, 1991. There were 1.3 attempts for each successful umbilical blood sampling. The overall success rate was 94%. The first-year fellows-in-training attempted 61 procedures with a 90.2% success rate within two attempts and an overall success rate of 95.1%. Second-year fellows attempted 32 procedures with a 93.8% success rate within two attempts and an overall success rate of 93.8%. Procedure-related complications included five episodes of fetal bradycardia (one resulting in a stillbirth at 20 weeks) and a single case of chorioamnionitis. Of the three perinatal deaths, two were associated with severe congenital anomalies resulting in a corrected procedure-related mortality rate of 1%. The morbidity and mortality associated with cordocentesis appears to be relatively low and fellows-in-training can perform such procedures with no apparent increase in complications if appropriately supervised.

Blood Specimen Collection↗
PubMed1991

Diagnosis of chlamydial infection in pregnant women using the Testpack Chlamydia diagnostic kit.

We compared the performance of Testpack Chlamydia to tissue culture isolation for detection of endocervical chlamydia in an obstetric clinic population at high risk for infection. Among 227 evaluable patients, 30 tissue culture-confirmed chlamydial infections were found (13.2%). The sensitivity, specificity, and positive and negative predictive values of Testpack compared with tissue culture isolation were 66.7, 95.4, 69.0, and 94.9%, respectively. This test can be performed on a desktop within 30 minutes by staff with limited laboratory experience and no special equipment. Based upon our preliminary experience, we believe that Testpack Chlamydia offers promise as a screening device for the detection of endocervical chlamydial infections in high-risk obstetric populations.

Chlamydia Infections↗
PubMed1990

Optic nerve head extracellular matrix in primary optic atrophy and experimental glaucoma.

Unilateral glaucomatous optic neuropathy and optic nerve transections were produced in cynomolgus monkeys, and the optic nerve heads were examined by light and electron microscopic immunohistochemistry. Glaucomatous nerve heads showed increased labeling for collagen type IV along the margins of beams in the lamina cribrosa, due to accumulation of basement membrane-like materials. We also noted material in the pores of the laminar beams that labeled with antibodies to collagen types I, III and IV, but not elastin. In transected eyes, increased type IV labeling of laminar beam margins resulted solely from redundant astrocyte basement membranes. Extracellular matrix deposition within laminar pores was not observed following optic nerve transection; hence this may be a selective response to elevated intraocular pressure. This response may alter the biochemical composition of the lamina cribrosa and its function in patients with elevated intraocular pressure.

Animals↗
PubMed1990

Hemoperitoneum as a result of coital injury without associated vaginal injury.

Hemoperitoneum as a result of coital injury without associated vaginal injury is an extremely rare entity, and evidence by only five cases that have been reported in the medical literature to date. We report five additional cases encountered in two medical centers. Two of these were ruptured corpus luteum cysts, one was a laceration of the round ligament, another was a laceration of an ovary, and the fifth was rupture of a serous cystadenoma. This diagnosis should be considered in patients with hemoperitoneum after coitus.

Adult↗
PubMed1990

Plasma exchange for preeclampsia. I. Postpartum use for persistently severe preeclampsia-eclampsia with HELLP syndrome.

The postpartum use of plasma exchange with fresh-frozen plasma was assessed in a group of seven women with severe preeclampsia-eclampsia and HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) that persisted greater than 72 hours after delivery. During the study interval in which a total of 107 gravid women with HELLP syndrome were seen in our referral center, these seven patients (6.5%) demonstrated persistent thrombocytopenia (platelet count usually less than 30,000/mm3), rising lactic dehydrogenase (greater than 1000 IU/L) and evidence of multiorgan dysfunction. The seven case histories emphasize the variety of clinical and laboratory profiles that can be encountered in this small group of gravid women at risk for severe morbidity or mortality. Up to three 3 L plasma exchanges were required to effect permanent disease arrest and reversal. Utilization of the IBM 2997 Cell Separator system permitted bedside performance of procedures with enhanced convenience and optimal medical management. Successful plasma exchange was associated with (1) sustained increases in the mean platelet count at 24, 48, and 72 hours that were 2.2, 3.6, and 4.5 times the preexchange platelet counts and (2) a decreasing trend in lactic dehydrogenase concentrations below 1000 IU/L within 48 hours of exchange plasmapheresis. The current series of patients supports our recommendation that a trial of plasma exchange(s) with fresh-frozen plasma be considered for treatment of the infrequent postpartum case of HELLP syndrome that fails to abate within 72 hours of delivery and in which other evidence develops of an ongoing, widespread, and life-threatening thrombotic microangiopathy.

Adolescent↗
PubMed1990

Pregnancy complicated by preeclampsia-eclampsia with the syndrome of hemolysis, elevated liver enzymes, and low platelet count: how rapid is postpartum recovery?

The rapidity of postpartum disease recovery for severe preeclampsia associated with hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome) has not been well studied. Between January 1980 and March 1989, 158 pregnancies with preeclampsia-eclampsia complicated by HELLP syndrome were managed at the University of Mississippi Medical Center. The 70 patients with platelet nadir below 50,000/microL (class 1 HELLP syndrome) required as long as 11 days for all members to achieve a platelet recovery concentration of more than 100,000/microL, whereas all 88 gravidas with platelet nadir between 50,000-100,000/microL (class 2 HELLP syndrome) exceeded this platelet concentration by the sixth postpartum day, a statistically significant difference (P less than .0001). The interval between delivery and the onset of diuresis (mean +/- SD) was significantly longer in class 1 than in class 2 patients with milder disease (22.7 +/- 18.9 compared with 15.9 +/- 11.1 hours). Significantly more postpartum days were required in class 1 than in class 2 HELLP parturients for the lactic dehydrogenase (LDH) concentration to decrease below 500 IU/L (4.2 +/- 4.9 compared with 3.2 +/- 2.7 days). No women in the class 2 group required plasma exchange therapy to effect disease arrest and reversal, but 11 of 58 severely ill women in class 1 were treated with this modality. We conclude that the platelet count and LDH serum concentration, as indicators of HELLP severity and recovery, are clinically useful tools and that a more protracted postpartum recovery period should be expected for progressively severe expressions of HELLP syndrome.

Alanine Transaminase↗