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Biomedical subjects

C Lockwood

Publications and source records attributed to C Lockwood.

At least 19 recordsLinked to original sources
PubMed2001

Cervical length after multifetal pregnancy reduction in remaining twin gestations.

OBJECTIVE: Multifetal pregnancy reduction is associated with an increased risk of prematurity. Because cervical length correlates with preterm delivery risk, we sought to determine whether multifetal pregnancy reduction twin gestations are associated with shorter cervical lengths compared with non-multifetal pregnancy reduction twins. STUDY DESIGN: We compared an historic cohort of patients who underwent multifetal pregnancy reduction to twins (n = 35) to a control group of twin gestations without multifetal pregnancy reduction (n = 83) from July 1996 to January 2000. Both groups of patients were treated with identical protocols. Cervical lengths across gestation and pregnancy outcomes were compared. RESULTS: Study and control groups did not differ significantly in mean maternal age (37.8 +/- 4.9 years vs 35.5 +/- 6.2 years; P =.06), median parity (0 [range, 0-1] vs 0 [range, 0-2]; P =.56), or mean gestational age at delivery (36.2 +/- 2.6 weeks vs 35.8 +/- 3.8 weeks; P =.50). The proportion delivering before 35 weeks of gestation was not significantly different (14.3% vs 30.1%; P =.10) nor was delivery before 32 weeks of gestation (8.6% vs 8.4%; P =.98). Cervical length did not differ significantly between the 2 groups. At 14 to 19 weeks the median was 3.9 cm (range, 2.4-6.0 cm) in the multifetal pregnancy reduction group versus 3.7 cm (range, 3.1-4.7 cm) in the control subjects (P =.15); at 20 to 25 weeks, the medians were 3.2 cm (range, 2.2-5.4 cm) and 3.7 cm (range, 1.5-5.7 cm), respectively (P =.43); and at 26 to 31 weeks the medians were 3.5 cm (range, 1.2-5.9 cm) versus 3.8 cm (range, 1.2-5.3 cm), respectively (P =.56). CONCLUSION: Cervical length across gestation in twin pregnancies is not affected by multifetal pregnancy reduction, despite the likely inflammatory response expected to accompany this procedure.

Cervix Uteri↗
PubMed1997

The ability of the Haemonetics 4 Cell Saver System to remove tissue factor from blood contaminated with amniotic fluid.

UNLABELLED: The purpose of this study was to determine whether functionally active tissue factor could be removed from blood contaminated with amniotic fluid (AF) after processing through a Haemonetics 4 Cell Saver System (Haemonetics Corporation, Braintree, MA). In Phase I, AF was collected from 29 women undergoing cesarean section. Nine experiments were performed. Forty-milliliter aliquots of pooled AF were mixed with 125 mL of packed red blood cells and processed in the Cell Saver. In Phase II, all the blood and AF lost at cesarean section was collected and processed through the Cell Saver. Pre- and postwash specimens were collected and analyzed for total tissue factor concentration and the concentration of functionally active tissue factor. In Phase I, total tissue factor concentration was reduced by 89%, and the concentration of active tissue factor was reduced to 0 after processing. In Phase II, no tissue factor was detected after processing through the Cell Saver. We have demonstrated the ability of the Haemonetics 4 Cell Saver System to remove tissue factor activity from blood contaminated with AF. IMPLICATIONS: Hemorrhage after childbirth may require massive transfusion. If the patient's own blood can be collected and given back to the patient, this may avoid the use of regular banked blood. Amniotic fluid, which may mix with blood lost after delivery, contains tissue factor, a substance that may activate the coagulation system and cause further bleeding. The authors found that the Haemonetics 4 Cell Saver System (Haemonetics Corporation, Braintree, MA), which collects and washes blood, can remove tissue factor from blood contaminated with amniotic fluid.

Amniotic Fluid↗
PubMed1997

A short-term clinical study design to investigate the chemical plaque inhibitory properties of mouthrinses when used as adjuncts to toothpastes: applied to chlorhexidine.

The removal of plaque by toothbrushing with toothpaste is the most common form of plaque control in the developed world. However, the use of chemical adjuncts such as mouthrinses is increasing. In practice mouthrinses and toothpaste are used together, however, in many clinical trials, employed to assess mouthrinse activity, toothpaste use is suspended. This fails to measure the effect of chemical interactions which are known to occur between toothpaste ingredients and mouthrinses. The objective of this trial was to develop a methodology which would assess the adjunctive chemical plaque inhibitory action of mouthrinses, when used with toothpaste but without the indeterminate variable of toothbrushing. The study was a single blind, randomised, 7-way crossover design, based on a variation of a 4 day plaque regrowth model. The 2 x daily rinsing regimens produced increasing plaque scores in the following order: (1) water/chlorhexidine, (2) chlorhexidine/water, (3) chlorhexidine/toothpaste slurry, (4) toothpaste slurry/chlorhexidine, (5) water/toothpaste slurry, (6) toothpaste slurry/water, (7) water/water. Chlorhexidine and water or chlorhexidine and toothpaste slurry combinations produced significantly lower plaque scores than water alone. Slurry and water combinations resulted in less plaque than water alone, but differences were not significant. Toothpaste slurry and chlorhexidine produced significantly increased plaque scores compared to chlorhexidine and water. The study suggests that, outside the Hawthorne effect, chlorhexidine rinses would be less effective in reducing plaque when used with toothpaste than when used alone. The methodology could be employed as a screening tool for the evaluation of mouthrinses expected to be used as adjuncts to normal oral hygiene methods. The same could be used to optimise oral hygiene regimens which include the use of mouthrinses.

Adult↗
PubMed1996

The clinical outcome of preterm premature rupture of membranes in twin versus singleton pregnancies.

The purpose of this study was to determine the clinical outcome of preterm premature rupture of the membranes (PPROM) in twin versus singleton pregnancies at less than or equal to 36 weeks' gestation. A retrospective cohort study was conducted in 116 twin pregnancies with PPROM at less than or equal to 36 weeks' gestational age and 116 matched singleton pregnancies. The two groups were analyzed for differences in maternal demographics and perinatal and neonatal outcome. Perinatal and neonatal outcomes were similar in the two groups. The median latency period, however, was significantly decreased in the twin group (11.4 hours, Inter Quartile Range: 6.3-26.4) versus the singleton group (19.5 hours, Inter Quartile Range: 10.2-49.3, p < 0.05). The latency period in each group was notably longer when PPROM occurred at less than 30 weeks' gestation, but was still shorter in the twin pregnancies (27.6 hours, Inter Quartile Range: 20-307 versus 75.1 hours, Inter Quartile Range: 15-189, p < 0.05). Twin pregnancies with PPROM at less than or equal to 36 weeks' gestational age have a decreased latency period when compared to matched singletons. The perinatal and neonatal outcomes, however, are similar.

Adult↗
PubMed1994

The effect of placenta previa on blood loss in second-trimester pregnancy termination.

OBJECTIVE: To determine whether placenta previa increases bleeding during second-trimester pregnancy termination. METHODS: The records of 131 consecutive women undergoing elective pregnancy termination at 13-24 weeks' gestation were reviewed and divided into those with and without placenta previa based on an ultrasound examination before the procedure. These two groups were then compared for differences in maternal characteristics, estimated blood loss, operative time, infection, and hospital admission. RESULTS: Twenty-three of 131 women (17.6%) had placenta previa. Sixty-seven percent of the previa patients smoked, versus 37% in the control group, a statistically significant difference. A statistical difference was noted with respect to placenta previa in intraoperative blood loss (P < .05), but not operative time, time to discharge, infection, hemorrhage, or other complications. CONCLUSION: Second-trimester pregnancy terminations in the presence of placenta previa are associated with a higher estimated blood loss, but no apparent increase in abortion-related infection, postoperative transfusion requirements, hysterectomy, or other complications.

Abortion, Therapeutic↗
PubMed1993

Walker-Warburg syndrome: prenatal ultrasound findings.

The prenatal sonographic findings in a case of Walker-Warburg syndrome are described. The patient was not at risk for this condition. Ultrasound examination at 34 weeks' gestation revealed hydrocephaly, Dandy-Walker anomaly, and striking ocular abnormalities. From a review of the literature it appears that while intracranial abnormalities can lead to the diagnosis in cases at risk for this syndrome, ocular abnormalities are rather characteristic for this syndrome and they should be searched for in every case of hydrocephaly or encephalocele.

Abnormalities, Multiple↗
PubMed1988

Ultrasonographic assessment of gestational age with the distal femoral and proximal tibial ossification centers in the third trimester.

A prospective sonographic evaluation of the distal femoral and proximal tibial epiphyseal ossification centers in 228 normal pregnant women was carried out from 28 to 40 weeks' gestation. The mean gestational age at which the distal femoral epiphysis and proximal tibial epiphysis were imaged was 34 and 38 weeks, respectively. The distal femoral epiphysis was not identifiable before 28 weeks but was observed in 72% of fetuses at 33 weeks and in 94% of fetuses at 34 weeks' gestation. The presence of a distal femoral epiphysis measuring 1 or 2 mm was associated with a gestational age of greater than 33 weeks in 87.0% of fetuses, whereas a distal femoral epiphysis measuring greater than or equal to 3 mm was associated with a gestational age greater than 37 weeks in 85% of fetuses. The proximal tibial epiphysis, which was absent before 34 weeks' gestation, was observed in 56% of fetuses at 36 weeks, in 80% of fetuses at 37 weeks, and in 100% of fetuses at 39 weeks of gestation. The presence of a proximal tibial epiphysis of 1 or 2 mm was associated with a gestational age of greater than 36 weeks in 88% of fetuses, whereas a proximal tibial epiphysis greater than or equal to 3 mm was associated with a gestational age of greater than 38 weeks in 94% of fetuses. The sonographic evaluation of distal femoral epiphysis/proximal tibial epiphysis can be used as independent markers for estimation of gestational age during the third trimester, a period in which standard fetal biometric estimates of gestational age are least accurate.

Epiphyses↗
PubMed1988

The prenatal sonographic diagnosis of lethal multiple pterygium syndrome: a heritable cause of recurrent abortion.

Presumably, a large number of recurrent abortions are caused by lethal recessive syndromes whose diagnosis depends either on a known family history or on the identification of characteristic fetal phenotypic features on pathologic examination. Because these conditions are rare, family histories are seldom helpful, and nondirected postmortem examinations on degenerating samples are seldom enlightening. Serial ultrasonography beginning early in pregnancy may provide important information in the evaluation of recurrent abortion caused by lethal recessive disorders. Reported is the accurate prenatal sonographic diagnosis of lethal multiple pterygium syndrome in a patient with a history of recurrent abortions. This syndrome is characterized by multiple limb contractures with pterygia, facial clefting, intracranial abnormalities, cystic hygroma, progressive fetal edema, and fetal death by midgestation. Inheritance may be X-linked recessive. Lethal multiple pterygium syndrome should be considered in patients with a history of recurrent midtrimester losses.

Abnormalities, Multiple↗
PubMed1988

Amniotic band syndrome in monozygotic twins: prenatal diagnosis and pathogenesis.

Amniotic band syndrome is a well-described disorder lacking a precise definition or a scientifically validated hypothesis of pathogenesis. The widely accepted "exogenous" theory suggests that early amniotic rupture leads to the formation of pathologic amniotic strands, which then induce nonanatomic fetal abnormalities. This paradigm appears to be challenged by observations that amniotic band syndrome occurs in monozygotic twin gestations. The exclusive development of amniotic band syndrome in monozygotic versus dizygotic twin gestations, the description of early amniotic rupture in one sac of a dizygotic twin gestation without subsequent fetal abnormalities, and the paradoxical observations of discordance in monoamniotic and concordance in diamniotic twin gestations, fail to support an "exogenous" etiology for amniotic band syndrome.

Amniocentesis↗
PubMed1988

Hereditary angioedema and immunoglobulin A deficiency in pregnancy.

Hereditary angioedema is a rare immunologic disorder, and immunoglobulin A deficiency is the most common isolated immunodeficiency. These rarely coexisting conditions may affect pregnancy. We report a gravida with the combination who developed severe acute laryngeal edema.

Adult↗
PubMed1987

A sonographic screening method for Down syndrome.

We describe a potential screening method for the second trimester detection of the fetus with Down syndrome by the use of standard sonographic biometry. Retrospective assessment of the biparietal diameter, femur length, and biparietal diameter/femur length ratio in 55 fetuses with Down syndrome and 544 control fetuses was performed at two medical centers. Adequate numbers of cases and controls were available to permit statistically significant comparisons between the groups at 15 to 23 weeks' gestation. Fetuses with Down syndrome displayed no statistically significant differences in the cephalic index or the biparietal diameter compared with controls at a given gestational age. Significant femur length shortening was observed, but the greatest statistical difference was noted for the biparietal diameter/femur length ratio. This ratio was found to decrease with gestational age in the normal population and was consistently elevated in the Down syndrome population (compared with control) throughout the second trimester. With a cutoff value of 1.5 SD above the normal population mean for the biparietal diameter/femur length ratio, 50% to 70% of fetuses with Down syndrome could be identified in 6% of the total population (p less than 0.0001). This preliminary study suggests that the biparietal diameter/femur length ratio may prove superior to current Down syndrome screening methods and, as a third independent variable, may significantly enhance the sensitivity and specificity of combined maternal age/maternal serum alpha-fetoprotein screening modalities.

Down Syndrome↗