Biomedical subjects

J C Morrison

Publications and source records attributed to J C Morrison.

At least 73 records · Page 4Linked to original sources

PubMed1998

A comparative study of ketorolac (Toradol) and magnesium sulfate for arrest of preterm labor.

BACKGROUND: We evaluated the efficacy and safety of ketorolac (Toradol). METHODS: In this prospective trial, 88 women in confirmed preterm labor at < or =32 weeks' gestation were randomized to receive magnesium sulfate given as an initial 6 g intravenous bolus followed by continuous infusion therapy (2 to 6 g/hr) or intramuscularly administered ketorolac (60 mg loading dose) followed by 30 mg every 6 hours for a maximum of 24 hours. RESULTS: The study groups were similar with respect to age, parity, cervical status, and gestational age on admission. Ketorolac was more rapid (2.71 hr+/-2.16) in the arrest of preterm labor than was magnesium sulfate (6.22 hr+/-5.65). No patient required discontinuance of either drug due to adverse effects. There was no difference in the incidence of neonatal complications between the two groups. CONCLUSION: In gestations with preterm labor at <32 weeks, ketorolac appears to be an appropriate first-line tocolytic agent.

Adult↗

PubMed1998

Do multiple measurements employing different ultrasonic techniques improve the accuracy of amniotic fluid volume assessment?

This investigation was undertaken to determine if the accuracy of the ultrasound assessment of abnormal amniotic fluid volume (oligohydramnios or polyhydramnios) is improved by employing multiple sonographic amniotic fluid measurements. Four ultrasound techniques consisting of the subjective assessment (ultrasonic visualization without measurement), largest vertical pocket, amniotic fluid index and 2-diameter pocket technique were performed followed by amniocentesis and dye-dilution confirmation of amniotic fluid volume in 66 singleton pregnancies. The ultrasound accuracy to detect abnormal amniotic fluid volume ranged from 61% with the largest vertical pocket to 70% with the 2-diameter pocket procedure used separately. Receiver operator characteristic curves demonstrated that combining the 4 ultrasonic measurements did not improve the accuracy of identifying amniotic fluid volumes.

Adolescent↗

PubMed1998

Childhood pyelonephritis: comparison of gadolinium-enhanced MR imaging and renal cortical scintigraphy for diagnosis.

PURPOSE: To compare gadolinium-enhanced inversion-recovery magnetic resonance (MR) imaging with renal cortical scintigraphy in the diagnosis of childhood pyelonephritis. MATERIALS AND METHODS: Thirty-seven patients with fever-producing urinary tract infection underwent gadolinium-enhanced inversion-recovery MR imaging and technetium-99m renal cortical scintigraphy. Each study was read in double-blind fashion by two radiologists. The kidney was divided into three zones, and each was graded as positive, equivocal, or negative for pyelonephritis. RESULTS: Seventy kidneys (210 zones) were imaged. Twenty-six kidneys (54 zones) had evidence of pyelonephritis at both MR imaging and scintigraphy. Twenty-four kidneys (100 zones) were negative on both studies. Twelve kidneys (42 zones) were positive at MR imaging but negative at scintigraphy, and four kidneys (seven zones) were negative at MR imaging but positive at scintigraphy. The results of MR imaging for pyelonephritis were not equivalent to the results of scintigraphy (P = .001 for renal zones). The proportion of positive agreement between readers for the presence of pyelonephritis was 0.85 and 0.57 for MR imaging and scintigraphy, respectively. The proportion of negative agreement was 0.88 and 0.80 for MR imaging and scintigraphy, respectively. CONCLUSION: Gadolinium-enhanced inversion-recovery MR imaging enabled detection of more pyelonephritic lesions than did renal cortical scintigraphy and had superior interobserver agreement.

Adolescent↗

PubMed1998

Prospects for genetic intervention in primary open-angle glaucoma.

Recent advances in glaucoma genetics hold potential for dramatically changing the clinical care of glaucoma patients. To date, 5 primary open-angle glaucoma genes and 2 congenital glaucoma genes have been mapped. As more glaucoma genes are identified, earlier diagnosis for glaucoma should become more readily available. Progress in molecular genetics holds considerable promise for both current and future therapy of glaucoma. Glaucoma classification will be tailored to each individual based upon that person's family history, i.e. family glaucoma genotype. In the future, the optimum treatment for a specific glaucoma patient might rely on the knowledge of the phenotype of that person's causal gene, without having to resort to 'trial and error'. At this time, glaucoma treatment is restricted to lowering intraocular pressure. In the near future, with the knowledge of the pathophysiology caused by the defective glaucoma gene, more traditional drug treatments may be used to bypass the gene defect. Ultimately, gene therapy would replace the mutant gene with a normal one before visual loss has occurred as has been done with a model for retinitis pigmentosa, the retinal degeneration mouse.

Forecasting↗

PubMed1998

Mathematical models to correlate amniotic fluid index and amniotic fluid volume.

PURPOSE: To describe a predictable relationship that relates amniotic fluid index (AFI) to amniotic fluid volume (AFV) and improve the accuracy of AFI to detect true oligohydramnios. METHODS: Data from 42 parturients (group I) who underwent measurements of amniotic fluid sonographically (amniotic fluid index) as well as by dye-dilution technique was used to relate AFI to AFV. Subsequently, 22 consecutive women (group II) were used to test the accuracy of the equation to predict true oligohydramnios. RESULTS: In group II, 11 of 22 patients had true oligohydramnios and the sensitivity, specificity, positive and negative predictive values of AFI < or = 5.0 to detect a confirmed AFV < 500 mL were 0%, 91%, 0%, and 48%, respectively. These values of AFI, when used in conjunction with the equation, improved to 73%, 55%, 62%, 67%, respectively. With AFI and the equation, significantly more patients in group II with true oligohydramnios (8 of 11) could be detected than with using AFI alone (0 of 11; p = 0.002). CONCLUSION: AFI is poor predictor of true oligohydramnios. Using the mathematical model, the detection rate of oligohydramnios is significantly improved.

Amniotic Fluid↗

PubMed1998

Comparison of insulin regimens and administration modalities in pregnancy complicated by diabetes.

PURPOSE: To compare insulin administration using premixed insulin (70% NPH/30% Regular) by an injectable pen with traditional self-mixed insulin administered by syringe. METHODS: In this study, 93 women were enrolled into four groups.: 1) self-mixed/syringe, 2) premixed/syringe, 3) self-mixed/pen, and 4) premixed/pen. RESULTS: Women in the premixed pen group had significantly less cesarean deliveries for failure to progress in labor and a decrease (not significant) in postpartum infection and infant macrosomia. Patients felt premixed insulin administered by the pen was easier to use. No significant differences were noted in glucose control, compliance among the four groups, or cost. CONCLUSION: Premixed insulin administration via the pen is safe, effective and no more costly than traditional treatment for pregnant diabetic women.

Adolescent↗

PubMed1998

Glaucoma drops control intraocular pressure and protect optic nerves in a rat model of glaucoma.

PURPOSE: To determine whether chronic topical glaucoma therapy can control intraocular pressure (IOP) and protect nerve fibers in a rat model of pressure-induced optic nerve damage. METHODS: Sixteen adult Brown Norway rats were-administered unilateral episcleral vein injections of hypertonic saline to produce scarring of the aqueous humor outflow pathways. Twice daily applications of either artificial tears (n = 6), 0.5% betaxolol (n = 5), or 0.5% apraclonidine (n = 5) were delivered to both eyes, and awake pressures were monitored with a TonoPen XL tonometer for 17 days before the rats were killed. RESULTS: For animals administered artificial tears, the mean IOP of the experimental eyes was 39 +/- 2 mm Hg compared with 29 +/- 1 mm Hg for the control eyes. This difference was statistically significant (P < 0.001). Mean IOPs in the experimental eyes of animals administered betaxolol and apraclonidine were 29 +/- 7 and 29 +/- 4 mm Hg, respectively, whereas the mean IOP in the control eyes was 28 +/- 1 mm Hg for both groups. There was no statistically significant difference among these values. The mean IOP for the experimental eyes in the betaxolol and apraclonidine groups was lower than that in animals administered artificial tears (P = 0.003). Quantitative histologic analysis of optic nerve damage in experimental eyes showed that four of the six animals administered artificial tears had damage involving 100% of the neural area. This degree of damage appeared in only 3 of 10 animals administered glaucoma therapy. Optic nerve protection was closely correlated with IOP history because damage was limited to less than 10% of the cross-sectional area in all animals in which the maximal IOP was less than or equal to 39 mm Hg, more than 2 SD below the mean value for eyes administered artificial tears. CONCLUSIONS: Topical glaucoma therapy in this model can prevent IOP elevation and protect optic nerve fibers.

Adrenergic alpha-Agonists↗

PubMed1998

Oral magnesium for tocolysis: a comparison of magnesium gluconate and enteric-coated magnesium chloride.

PURPOSE: Following parenteral magnesium tocolysis for patients in preterm labor. The choice of oral tocolytic medications is controversial. METHODS: Over a six-month period, 47 patients who were inpreterm labor were randomized after parenteral magnesium tocolysis to receive magnesium gluconate ([Mg-g] 648 mg elemental magnesium/day) or magnesium chloride ([Mg-c] 640 mg elemental magnesium/ day). A serum magnesium was obtained 24 hours after the initiation of oral therapy. RESULTS: In the 25 patients were treated with Mg-g and 22 with Mg-c there were no differences in patient demographics, initial cervical dilatation hours on parenteral magnesium sulfate, recurrent contractions, or side effects between the two groups. The cost was also similar (Mg-c, $1.40/d; Mg-g, $2.11/d). The serum magnesium levels were higher in the Mg-c group (1.80 +/- 0.28 mg/dl) compared to the Mg-g group (1.63 +/- 0.30 mg/dl) but the difference was not significant. CONCLUSION: These two preparations of magnesium are similar in their effects on uterine activity and serum levels when used at these dosages.

Administration, Oral↗

PubMed1998

Comparison of insulin regimens and administration modalities in pregnancy complicated by diabetes.

PURPOSE: To compare insulin administration using premixed insulin (70% NPH/30% Regular) by an injectable pen with traditional self-mixed insulin administered by syringe. METHODS: In this study, 93 women were enrolled into four groups: 1) self-mixed/syringe, 2) premixed/syringe, 3) self-mixed/pen, and 4) premixed/pen. RESULTS: Women in the premixed pen group had significantly less cesarean deliveries for failure to progress in labor and a decrease (not significant) in postpartum infection and infant macrosomia. Patients felt premixed insulin administered by the pen was easier to use. No significant differences were noted in glucose control, compliance among the four groups, or cost. CONCLUSION: Premixed insulin administration via the pen is safe, effective and no more costly than traditional treatment for pregnant diabetic women.

Blood Glucose↗

PubMed1998

Amnioinfusion-induced malpresentation.

Amnioinfusion is a valuable and common intrapartum procedure for the relief of cord compression and to dilute thick meconium. Like most procedures, it is not without risk and we report a case of malpresentation following amnioinfusion. Intrapartum fetal demise occurred after malpresentation during amnioinfusion resulting in a change of fetal presentation from vertex to unrecognized shoulder presentation. Further study is needed regarding changes in volume of amniotic fluid and saline as well as intrauterine manipulation and the effect on fetal presentation. Careful attention must be paid to infused volumes during amnioinfusion.

Adult↗

PubMed1998

Hematological complications of Gaucher's disease in pregnancy.

A case is presented of a 31-year-old Filipino female, gravida 5 para 2, at 38 weeks plus 5 days gestation, with known type I Gaucher's disease who underwent repeat cesarean delivery. After cesarean delivery, the patient developed disseminated intravascular coagulation and required transfusion of eight 6-packs of platelets, 6 units of fresh frozen plasma, two 10-packs of cryoprecipitate, and 6 units of packed red blood cells. Pregnancy is generally well tolerated in patients with type I Gaucher's disease, an autosomal recessive lysosomal storage disorder in which lipid deposits accumulate in the liver, spleen, and bone marrow. Hemorrhagic problems secondary to severe thrombocytopenia may develop postpartum in pregnancies complicated by Gaucher's disease, requiring significant support with blood and blood products.

Adult↗

PubMed1997

The accuracy of ultrasound evaluation of amniotic fluid volume in singleton pregnancies: the effect of operator experience and ultrasound interpretative technique.

The objective of this study was to evaluate the effect of operator experience and ultrasound interpretation technique on the accuracy of ultrasound estimates of amniotic fluid volume. Ultrasound evaluation was carried out by an obstetric resident, a nurse sonographer, a maternal-fetal medicine fellow, and a maternal-fetal medicine staff member to subjectively estimate (visual interpretation without sonographic measurements) amniotic fluid volume in 63 pregnancies. Amniotic fluid volume was also evaluated using ultrasound measurements based on the largest vertical pocket technique, the amniotic fluid index, and the two-diameter pocket method. The accuracy of these ultrasound estimates was assessed by comparing the ultrasound results to actual amniotic fluid volume as determined by a dye-dilution technique. For analysis, amniotic fluid volumes were classified as oligohydramnios, normal, or hydramnios using established volumetric criteria for singleton pregnancies. Subjective estimates ranged from 65% to 70% correct and did not differ by operator experience except for the more accurate diagnosis of hydramnios by the maternal-fetal medicine staff. The three sonographic measurements were similar in overall accuracy (59-67%). The two-diameter pocket method was, however, significantly more accurate in identifying oligohydramnios. It appears that neither operator experience nor sonographic technique greatly affects the accuracy of ultrasound estimates of amniotic fluid volume.

Adolescent↗

PubMed1997

A rat model of chronic pressure-induced optic nerve damage.

To develop unilateral, chronically elevated intraocular pressure in rats, episcleral veins were injected with hypertonic saline and the intraocular pressure was monitored with a Tono-Pen XL tonometer. Histologic analyses of eyes with differing degrees and durations of intraocular pressure elevation were performed to ascertain the effects of these pressures on the optic nerve. Out of 20 consecutive animals, nine had elevations of intraocular pressure following a single injection, while subsequent injections raised intraocular pressure in seven others. One eye became hypotonous. In the remaining animals, subsequent injections sufficient to raise intraocular pressure were deliberately withheld, to determine the possible direct effects of injections on the optic nerve. Mean sustained pressure elevations ranged from 7 to 28 mm Hg and the retinal vasculature remained perfused in all eyes. Optic nerve cross sections from eyes without intraocular pressure elevation appeared identical to those from uninjected eyes, while nerves from eyes with the greatest intraocular pressure rise demonstrated axonal damage that involved 100% of the neural area. Eyes with either less severe pressure elevations or shorter durations showed partial damage, ranging from 0.5% to 10.4% of the neurla area. In 70% of these nerves, damage was concentrated in the superior temporal region. Within the optic nerve head, often associated with astrocytes, axons contained abnormal accumulations of membrane-bound vesicles and mitochondria. The anterior chamber angles showed sclerosis of the trabecular meshwork with anterior synechiae, but Schlemm's canal, collector channels and aqueous veins appeared patent. Unilateral sclerosis of the trabecular meshwork produces sustained elevation of intraocular pressure in rats with optic nerve damage that in many ways resembles that seen in human glaucoma. Understanding the mechanism of nerve damage in this model may provide new insights into the pathogenesis of human glaucoma.

Animals↗

PubMed1997

The accuracy of the summated amniotic fluid index in evaluating amniotic fluid volume in twin pregnancies.

OBJECTIVE: Our purpose was to determine the accuracy of the summated amniotic fluid index designed to estimate the total amniotic fluid volume in twin pregnancies. STUDY DESIGN: The summated amniotic fluid index was measured in 62 normal diamniotic twin pregnancies by adding the deepest vertical pockets in the four quadrants. Actual amniotic fluid volume was then determined in all 124 amniotic sacs by amniocentesis and a dye-dilution technique. For data analysis, amniotic fluid volumes were classified by percentile with use of previously reported norms. RESULTS: There were significant differences in the percentile distribution of amniotic fluid volume as estimated by the summated amniotic fluid index and the actual volume as determined by dye dilution (p < 0.001). The summated amniotic fluid index has a sensitivity of only 13% in predicting amniotic sac volume. CONCLUSION: The summated amniotic fluid index is a poor predictor of intertwin differences in amniotic fluid volume and cannot identify twin pairs at risk for oligohydramnios and hydramnios.

Adult↗

PubMed1997

A randomized trial of epidural anesthesia to improve external cephalic version success.

OBJECTIVE: This study was designed to determine whether epidural anesthesia would improve external cephalic version success in a safe and effective manner. STUDY DESIGN: All women > 37 weeks' gestation with breech presentation scheduled for external cephalic version at the medical center from Dec. 1, 1993, to July 31, 1996, were randomized to receive an epidural or no epidural anesthesia. Under ultrasonographic guidance up to three version attempts were performed. RESULTS: Sixty-nine women were randomized to receive epidural (n = 35) versus no epidural (n = 34) anesthesia for external cephalic version. There were no statistically significant differences in maternal age, parity, maternal weight, gestational age, estimated fetal weight, or station of the presenting part. The success rate was better for the epidural group (relative risk 2.12, 95% confidence interval 1.24 to 3.62). Neither anterior placentation or oligohydramnios affected the success rate. CONCLUSION: Epidural anesthesia increases success of external cephalic version without any apparent detrimental effect on the maternal-fetal unit.

Adult↗

PubMed1997

Nulliparous active labor, epidural analgesia, and cesarean delivery for dystocia.

OBJECTIVE: Our purpose was to examine the effect of epidural analgesia on dystocia-related cesarean delivery in actively laboring nulliparous women. STUDY DESIGN: Active labor was confirmed in nulliparous women by uterine contractions, cervical dilatation of 4 cm, effacement of 80%, and fetopelvic engagement. Patients were randomized to one of two groups: epidural analgesia or narcotics. A strict protocol for labor management was in place. Patients recorded the level of pain at randomization and at hourly intervals on a visual analog scale. Elective outlet operative vaginal delivery was permitted. RESULTS: One hundred women were randomized. No difference in the rate of cesarean delivery for dystocia was noted between the groups (epidural 8%, narcotic 6%; p = 0.71). No significant differences were noted in the lengths of the first (p = 0.54) or second (p = 0.55) stages of labor or in any other time variable. Women with epidural analgesia underwent operative vaginal delivery more frequently (p = 0.004). Pain scores were equivalent at randomization, but large differences existed at each hour thereafter. The number of patients randomized did not achieve prestudy estimates. A planned interim analysis of the results demonstrated that we were unlikely to find a statistically significant difference in cesarean delivery rates in a trial of reasonable duration. CONCLUSIONS: With strict criteria for the diagnosis of labor and with use of a rigid protocol for labor management, there was no increase in dystocia-related cesarean delivery with epidural analgesia.

Adult↗

PubMed1997

Ultrasonographic assessment of amniotic fluid does not reflect actual amniotic fluid volume.

OBJECTIVE: Our objective was to compare the ability of two methods of amniotic fluid assessment (two-diameter amniotic fluid pocket versus the amniotic fluid index) to predict oligohydramnios (actual amniotic fluid volume < 500 ml) or polyhydramnios (actual amniotic fluid volume > 1500 ml). STUDY DESIGN: The amniotic fluid index and the two-diameter amniotic fluid pocket were assessed before amniocentesis and determination of amniotic fluid volume with the dye (aminohippurate sodium)-dilution technique. To assess the detection of either oligohydramnios or polyhydramnios, the areas under the receiver-operator characteristic curves (+/-SE) were estimated by the point-to-point trapezoidal method of integration. Prediction limits were calculated by regression analysis of amniotic fluid index or two-diameter amniotic fluid pocket versus actual amniotic fluid volume and determination of 95th percentile ranges for amniotic fluid volume. RESULTS: We studied 144 patients with a mean (+/-SD) gestational age of 31.7 +/- 5.5 weeks; mean (+/-SD) amniotic fluid index and two-diameter amniotic fluid pocket were 12.6 +/- 6.1 cm and 21.2 +/- 18.4 cm2, respectively. Mean (+/-SD) actual amniotic fluid volume was 722 +/- 735 ml (range 101 to 4318 ml). The areas under the four receiver-operator characteristic curves were not significantly different from the nondiagnostic line (p < 0.05). Regression slopes (r values) for amniotic fluid index and two-diameter amniotic fluid pocket versus actual amniotic fluid volume were 0.34 and 0.23, respectively. Calculation of the prediction limit for 95% confidence that oligohydramnios is absent requires that the amniotic fluid index be 30 cm and the two-dimension amniotic fluid pocket be 90 cm2, both thresholds of which are currently considered to represent clinical polyhdramnios. CONCLUSIONS: Both amniotic fluid index and two-dimension amniotic fluid pocket appear to be inaccurate predictors of actual oligohydramnios or polyhydramnios when compared with dye-dilution calculations of actual amniotic fluid volume.

Adult↗

PubMed1997

Intrapartum oligohydramnios does not predict adverse peripartum outcome among high-risk parturients.

OBJECTIVE: Oligohydramnios can be defined by an amniotic fluid index < 5th percentile for gestational age or an amniotic fluid index < or = 5.0 cm regardless of gestational age. The purpose of this prospective study was to determine whether oligohydramnios by either definition predicts accurately, in a high-risk population, the risks for cesarean section for fetal distress, Apgar score < 7 at 5 minutes, and neonatal acidosis. STUDY DESIGN: An amniotic fluid index was obtained in 490 consecutive parturients with medical or obstetric complications and a reliable gestational age. After each delivery, an umbilical arterial blood gas analysis was obtained. Both measures of amniotic fluid index were rated as screening tests with use of sensitivity, specificity, predictive values, and receiver-operator characteristic curves. RESULTS: The incidences of cesarean section for fetal distress and umbilical arterial pH < 7.00 were 14% and 1.8%, respectively. The 70 neonates delivered by cesarean section for distress, compared with the 420 without, had a significantly higher incidence of pH < 7.00 (8.5% vs 0.7%, p = 0.0004, relative risk 5.0, 95% confidence interval 2.9 to 8.4). Sensitivity and positive predictive values of an amniotic fluid index < 5th percentile for gestational age to predict pH < 7.00 were 0.8% and 22%, respectively, and for an amniotic fluid index < or = 5.0 cm, 0.5% and 11%, respectively. Receiver-operator characteristic curves indicate that an amniotic fluid index between 0 and 20 cm cannot predict accurately which parturients will have cesarean sections for distress or be delivered of a newborn with a low Apgar score at 5 minutes or a pH < 7.10. CONCLUSION: Both criteria for oligohydramnios are poor predictors of adverse outcome for high-risk intrapartum patients.

Adolescent↗