Effect of recombinant human nerve growth factor treatment on corneal nerve regeneration in patients with neurotrophic keratopathy

Introduction

Neurotrophic Keratopathy (NK) is a neurodegenerative corneal disease that results in diminished corneal sensation. Previous studies have found that Cenegermin 0.002%, a recombinant human nerve growth factor (rhNGF), improves corneal epithelial healing in stage 2 and 3 NK patients. However, rhNGF effect on corneal sensation and nerve regeneration has not been well established. Thus, this study aims to analyze the effect of rhNGF on corneal nerve regeneration using in vivo confocal microscopy (IVCM) and on corneal sensitivity in NK patients.

Methods

This is a retrospective, longitudinal, case-control study that included patients with NK, treated with rhNGF for at least 4 weeks, with pre- and post-treatment IVCM images available for analysis. Chart reviews were conducted documenting prior medical and surgical history, clinical signs and symptoms, and corneal sensation using Cochet-Bonnet esthesiometry. Corneal nerve parameters were assessed by IVCM. Sex- and age-matched reference controls were selected from a database of healthy subjects for comparison.

Results

The study included 25 patients, with 22 (88%) stage 1, two (8%) stage 2, and 1 (4%) stage 3 NK patients, with a median age of 64 years (range: 30-93 years). Total, main, and branch nerve densities [median (range) in mm/mm2] were lower in the NK group pre-treatment [2.3 (0.0-21.1); 1.7 (0.0-13.0); 0.5 (0.0-10.2); respectively] vs. controls [22.3 (14.9-29.0); 10.1 (3.2-15.4); and 12.1 (6.2-18.4), (p < 0.0001 for all), respectively]. Post-treatment nerve densities increased compared to pre-treatment to 5.3 (0.0-19.4, p = 0.0083) for total, 3.5 (0.0-13.2, p = 0.0059) for main, and 2.0 (0.0-10.4, p = 0.0251) for branch nerves, but remained lower than controls (p < 0.0001 for all). Corneal sensation increased from 2.3 ± 1.1 cm pre-treatment to 4.1 ± 1.4 cm post-treatment (p = 0.001). Median best corrected visual acuity significantly increased following rhNGF treatment from 0.4 (0.0-1.6) to 0.12 (-0.1 to 1.6) (p = 0.007).

Conclusion

Patients with NK treated with at least 4 weeks of rhNGF, showed a significant increase in corneal nerve densities after treatment. A significant increase in corneal sensation, as well as best corrected visual acuity, was observed following treatment.

Corneal nerve regeneration is affected by scar location in herpes simplex keratitis: A longitudinal in vivo confocal microscopy study

PURPOSE

To assess the effect of corneal scar location on corneal nerve regeneration in patients with herpes simplex virus (HSV) keratitis in their affected and contralateral eyes over a 1-year period by in vivo confocal microscopy (IVCM), and to correlate these findings to corneal sensation measured by Cochet-Bonnet Esthesiometer.

METHODS

Prospective, longitudinal, case-control study. Bilateral corneal nerve density and corneal sensation were analyzed centrally and peripherally in 24 healthy controls and 23 patients with unilateral HSV-related corneal scars using IVCM.

RESULTS

In the central scar (CS) group, total nerve density in the central cornea remained significantly lower compared to controls at follow-up (11.05 ± 1.97mm/mm2, p < 0.001), and no significant nerve regeneration was observed (p = 0.090). At follow-up, total nerve density was not significantly different from controls in the central and peripheral cornea of the peripheral scar (PS) group (all p > 0.05), but significant nerve regeneration was observed in central corneas (16.39 ± 2.39mm/mm2, p = 0.007) compared to baseline. In contralateral eyes, no significant corneal nerve regeneration was observed in central or peripheral corneas of patients with central scars or peripheral scars at 1-year follow-up, compared to baseline (p > 0.05). There was a positive correlation between corneal nerve density and sensation in both central (R = 0.53, p < 0.0001) and peripheral corneas (R = 0.27, p = 0.0004). In the CS group, the corneal sensitivity was <4 cm in 4 (30.8%) and 7 (53.8%) patients in the central and peripheral corneas at baseline, and in 5 (38.5%) and 2 subjects (15.4%) at follow-up, whereas in the PS group only 1 patient (10%) showed a corneal sensation < 4 cm in the central cornea at baseline, and only 1 (10.0%), 3 (30.0%) and 1 (10.0%) patients at follow-up in the central, affected and opposite area of the cornea, respectively.

CONCLUSION

The location of HSV scarring in the cornea affects the level of corneal nerve regeneration. Eyes with central corneal scar have a diminished capacity to regenerate nerves in central cornea, show a more severe reduction in corneal sensation in the central and peripheral corneas that persist at follow-up, and have a reduced capability to restore the corneal sensitivity above the cut-off of 4 cm. Thus, clinicians should be aware that CS patients would benefit from closer monitoring for potential complications associated with neurotrophic keratopathy, as they have a lower likelihood for nerve regeneration.

A Single Administration of OC-01 (Varenicline Solution) Nasal Spray Induces Short-Term Alterations in Conjunctival Goblet Cells in Patients with Dry Eye Disease

INTRODUCTION

Dry eye disease is characterized by a persistently unstable or deficient tear film causing discomfort or visual impairment. Varenicline is a small-molecule nicotinic acetylcholine receptor agonist recently approved for use as a preservative-free nasal spray (OC-01 [varenicline solution] nasal spray [OC-01 VNS]) to treat signs and symptoms of dry eye disease, but its effect on conjunctival goblet cells has not been studied.

METHODS

In this phase 2, single-center, vehicle-controlled study, patients aged 18 years or more with a diagnosis of dry eye disease and Ocular Surface Disease Index© score of at least 23 were randomized 2:1 to receive a 50-µL single dose of OC-01 0.06 mg VNS or vehicle nasal spray in each nostril. Image assessments for area and perimeter were performed pre and 10 min post treatment for goblet cells by in vivo confocal microscopy and for meibomian glands by infrared meibography. Non-parametric Wilcoxon signed-rank test compared pre- and post-treatment measurements for each treatment group. Treatment-emergent adverse events (TEAEs) were assessed.

RESULTS

The study randomized 18 patients (mean age 61 years); 6 received vehicle (3/6 [50%] female) and 12 patients received OC-01 VNS (11/12 [92%] female). OC-01 VNS treatment decreased mean goblet cell area (pre-treatment, 106.4 µm2; post-treatment, 67.6 µm2; p = 0.02) and perimeter (pre-treatment, 38.9 µm; post-treatment, 31.2 µm; p = 0.03) but not vehicle did not (p = 0.25). There were no significant changes in mean meibomian gland area with either treatment (p ≥ 0.05). All TEAEs were non-ocular, non-serious, and mild.

CONCLUSIONS

This study demonstrated that a single administration of OC-01 0.06 mg VNS in patients with dry eye disease reduced conjunctival goblet cell area and perimeter, suggesting goblet cell degranulation and associated release of lubricating mucin. By activating the natural tear film, OC-01 VNS may provide benefits over topical medications.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03688802.

Alterations in corneal nerves in different subtypes of dry eye disease: An in vivo confocal microscopy study

PURPOSE

To evaluate corneal subbasal nerve alterations in evaporative and aqueous-deficient dry eye disease (DED) as compared to controls.

METHODS

In this retrospective, cross-sectional, controlled study, eyes with a tear break-up time of less than 10 s were classified as DED. Those with an anesthetized Schirmer's strip of less than 5 mm were classified as aqueous-deficient DED. Three representative in vivo confocal microscopy images were graded for each subject for total, main, and branch nerve density and numbers.

RESULTS

Compared to 42 healthy subjects (42 eyes), the 70 patients with DED (139 eyes) showed lower total (18,579.0 ± 687.7 μm/mm² vs. 21,014.7 ± 706.5, p = 0.026) and main (7,718.9 ± 273.9 vs. 9,561.4 ± 369.8, p < 0.001) nerve density, as well as lower total (15.5 ± 0.7/frame vs. 20.5 ± 1.3, p = 0.001), main (3.0 ± 0.1 vs. 3.8 ± 0.2, p = 0.001) and branch (12.5 ± 0.7 vs. 16.5 ± 1.2, p = 0.004) nerve numbers. Compared to the evaporative DED group, the aqueous-deficient DED group showed reduced total nerve density (19,969.9 ± 830.7 vs. 15,942.2 ± 1,135.7, p = 0.006), branch nerve density (11,964.9 ± 749.8 vs. 8,765.9 ± 798.5, p = 0.006), total nerves number (16.9 ± 0.8/frame vs. 13.0 ± 1.2, p = 0.002), and branch nerve number (13.8 ± 0.8 vs. 10.2 ± 1.1, p = 0.002).

CONCLUSIONS

Patients with DED demonstrate compromised corneal subbasal nerves, which is more pronounced in aqueous-deficient DED. This suggests a role for neurosensory abnormalities in the pathophysiology of DED.

Low-dose naltrexone is effective and well-tolerated for modulating symptoms in patients with neuropathic corneal pain

PURPOSE

Neuropathic corneal pain (NCP) is caused by damage or disease of the somatosensory nervous system that innervates the cornea and presents with symptoms of pain or persistent unpleasant sensations, such as burning, dryness, or light sensitivity. This retrospective study aims to assess the efficacy and tolerability of low-dose naltrexone (LDN) in refractory NCP patients.

METHODS

Fifty-nine NCP patients with a centralized component treated with oral LDN 4.5  mg at bedtime for at least four weeks were identified. Thirty out of 59 patients who had a baseline pain score ≥4 on the visual analogue scale had completed the ocular pain assessment survey (OPAS) and presented persistent pain, despite instillation of topical anesthetic drops, were included. Changes in pain scores, comorbidities, side effects, among others, were analyzed. Change in ocular pain scores (scale 0-10) and quality of life (QoL) scores (scale 0-100%) were the main endpoints.

RESULTS

Mean age (years ± SD) was 45.60 ± 19.30 with a white (80.00%) female (73.33%) predominance. Duration of LDN use was 14.87 ± 11.25 months, and the duration of NCP before treatment was 17.53 ± 17.29 months. Eight patients used LDN as a monotherapy, whereas the remaining used it as an adjunct therapy. LDN resulted in a 49.22% decrease in mean pain score from 6.13 ± 1.93 to 3.23 ± 2.60 (p < 0.001). Mean QoL scores by the OPAS were 5.84 ± 2.57 at the first visit and improved to 3.77 ± 2.91 at the last visit (p = 0.023). Common side effects were vivid dreams, headaches, and stomachache.

CONCLUSION

LDN was effective and well-tolerated for NCP treatment.

Efficacy and tolerability of nortriptyline in the management of neuropathic corneal pain

PURPOSE

Neuropathic corneal pain (NCP) is a recently acknowledged disease entity. However, there is no consensus in potential treatment strategies, particularly in patients with a centralized component of pain. This study aims to assess the efficacy and tolerability of the tricyclic antidepressant, nortriptyline, among NCP patients.

METHODS

Patients with clinically diagnosed NCP and a centralized component of pain, treated with oral nortriptyline, who had recorded pain scores as assessed by the ocular pain assessment survey at the first and last visit were included. Patients were excluded if they had any other ocular pathology that might result in pain or had less than 4 weeks of nortriptyline use. Demographics, time between visits, concomitant medications, systemic and ocular co-morbidities, duration of NCP, side effects, ocular pain scores, and quality of life (QoL) assessment were recorded.

RESULTS

Thirty patients with a mean age of 53.1 ± 18.5 were included. Male to female ratio was 8:22. Mean ocular pain in the past 24 h improved from 5.7 ± 2.1 to 3.6 ± 2.1 after 10.5 ± 9.1 months (p < 0.0001). Twelve patients (40.0%) had equal to or more than 50% improvement, 6 patients (20.0%) had 30-49% improvement, 6 patients (20.0%) had 1-29% improvement, 4 patients (13.3%) did not improve, while 2 patients (6.7%) reported increase in pain levels. Mean QoL improved from 6.0 ± 2.5 to 4.3 ± 2.4 (p = 0.019). Eight patients (26.6%) discontinued treatment due to persistent side effects, despite improvement by 22.4%.

CONCLUSION

Nortriptyline was effective in relieving NCP symptoms in patients with centralized component and insufficient response to other systemic and topical therapies who tolerated the drug for at least 4 weeks. Nortriptyline may be used in the management of patients with NCP.

The effect of size-scale on the kinematics of elastic energy release

Elastically-driven motion has been used as a strategy to achieve high speeds in small organisms and engineered micro-robotic devices. We examine the size-scaling relations determining the limit of elastic energy release from elastomer bands that efficiently cycle mechanical energy with minimal loss. The maximum center-of-mass velocity of the elastomer bands was found to be size-scale independent, while smaller bands demonstrated larger accelerations and shorter durations of elastic energy release. Scaling relationships determined from these measurements are consistent with the performance of small organisms and engineered devices which utilize elastic elements to power motion.

The Interaction of Compliance and Activation on the Force-Length Operating Range and Force Generating Capacity of Skeletal Muscle: A Computational Study using a Guinea Fowl Musculoskeletal Model

A muscle’s performance is influenced by where it operates on its force–length (F–L) curve. Here we explore how activation and tendon compliance interact to influence muscle operating lengths and force-generating capacity. To study this, we built a musculoskeletal model of the lower limb of the guinea fowl and simulated the F–L operating range during fixed-end fixed-posture contractions for 39 actuators under thousands of combinations of activation and posture using three different muscle models: Muscles with non-compliant tendons, muscles with compliant tendons but no activation-dependent shift in optimal fiber length (L0), and muscles with both compliant tendons and activation-dependent shifts in L0. We found that activation-dependent effects altered muscle fiber lengths up to 40% and increased or decreased force capacity by up to 50% during fixed-end contractions. Typically, activation-compliance effects reduce muscle force and are dominated by the effects of tendon compliance at high activations. At low activation, however, activation-dependent shifts in L0 are equally important and can result in relative force changes for low compliance muscles of up to 60%. There are regions of the F–L curve in which muscles are most sensitive to compliance and there are troughs of influence where these factors have little effect. These regions are hard to predict, though, because the magnitude and location of these areas of high and low sensitivity shift with compliance level. In this study we provide a map for when these effects will meaningfully influence force capacity and an example of their contributions to force production during a static task, namely standing.

Beyond power amplification: latch-mediated spring actuation is an emerging framework for the study of diverse elastic systems

Rapid biological movements, such as the extraordinary strikes of mantis shrimp and accelerations of jumping insects, have captivated generations of scientists and engineers. These organisms store energy in elastic structures (e.g. springs) and then rapidly release it using latches, such that movement is driven by the rapid conversion of stored elastic to kinetic energy using springs, with the dynamics of this conversion mediated by latches. Initially drawn to these systems by an interest in the muscle power limits of small jumping insects, biologists established the idea of power amplification, which refers both to a measurement technique and to a conceptual framework defined by the mechanical power output of a system exceeding muscle limits. However, the field of fast elastically driven movements has expanded to encompass diverse biological and synthetic systems that do not have muscles - such as the surface tension catapults of fungal spores and launches of plant seeds. Furthermore, while latches have been recognized as an essential part of many elastic systems, their role in mediating the storage and release of elastic energy from the spring is only now being elucidated. Here, we critically examine the metrics and concepts of power amplification and encourage a framework centered on latch-mediated spring actuation (LaMSA). We emphasize approaches and metrics of LaMSA systems that will forge a pathway toward a principled, interdisciplinary field.

The Influence of Visual, Vestibular, and Hindlimb Proprioceptive Ablations on Landing Preparation in Cane Toads

Coordinated landing from a jump requires preparation, which must include appropriate positioning and configuration of the landing limbs and body to be successful. While well studied in mammals, our lab has been using the cane toad (Rhinella marinus) as a model for understanding the biomechanics of controlled landing in anurans, animals that use jumping or bounding as their dominant mode of locomotion. In this article, we report new results from experiments designed to explore how different modes of sensory feedback contribute to previously identified features of coordinated landing in toads. More specifically, animals in which vision, hindlimb proprioception, or vestibular feedback were removed, underwent a series of hopping trials while high-speed video was used to record and characterize limb movements and electromyographic (EMG) activity was recorded from a major elbow extensor (anconeus). Results demonstrate that altering any sensory system impacts landing behavior, though loss of vision had the least effect. Blind animals showed significant differences in anconeus EMG timing relative to controls, but forelimb and hindlimb movements as well as the ability to successfully decelerate the body using the forelimbs were not affected. Compromising hindlimb proprioception led to distinctly different forelimb kinematics. Though EMG patterns were disrupted, animals in this condition were also able to decelerate after impact, though with less control, regularly allowing their trunks to make ground contact during landing. Animals with compromised vestibular systems showed the greatest deficits, both in takeoff and landing behavior, which were highly variable and rarely coordinated. Nevertheless, animals in this condition demonstrated EMG patterns and forelimb kinematics similar to those in control animals. The fact that no ablation entirely eliminates all aspects of landing preparation suggests that its underpinnings are complex and that there is no single sensory trigger for its initiation.

Smashing mantis shrimp strategically impact shells

Many predators fracture strong mollusk shells, requiring specialized weaponry and behaviors. The current shell fracture paradigm is based on jaw- and claw-based predators that slowly apply forces (high impulse, low peak force). However, predators also strike shells with transient intense impacts (low impulse, high peak force). Toward the goal of incorporating impact fracture strategies into the prevailing paradigm, we measured how mantis shrimp (Neogonodactylus bredini) impact snail shells, tested whether they strike shells in different locations depending on prey shape (Nerita spp., Cenchritis muricatus, Cerithium spp.) and deployed a physical model (Ninjabot) to test the effectiveness of strike locations. We found that, contrary to their formidable reputation, mantis shrimp struck shells tens to hundreds of times while targeting distinct shell locations. They consistently struck the aperture of globular shells and changed from the aperture to the apex of high-spired shells. Ninjabot tests revealed that mantis shrimp avoid strike locations that cause little damage and that reaching the threshold for eating soft tissue is increasingly difficult as fracture progresses. Their ballistic strategy requires feed-forward control, relying on extensive pre-strike set-up, unlike jaw- and claw-based strategies that can use real-time neural feedback when crushing. However, alongside this pre-processing cost to impact fracture comes the ability to circumvent gape limits and thus process larger prey. In sum, mantis shrimp target specific shell regions, alter their strategy depending on shell shape, and present a model system for studying the physics and materials of impact fracture in the context of the rich evolutionary history of predator-prey interactions.

Sensory feedback and coordinating asymmetrical landing in toads

Coordinated landing requires anticipating the timing and magnitude of impact, which in turn requires sensory input. To better understand how cane toads, well known for coordinated landing, prioritize visual versus vestibular feedback during hopping, we recorded forelimb joint angle patterns and electromyographic data from five animals hopping under two conditions that were designed to force animals to land with one forelimb well before the other. In one condition, landing asymmetry was due to mid-air rolling, created by an unstable takeoff surface. In this condition, visual, vestibular and proprioceptive information could be used to predict asymmetric landing. In the other, animals took off normally, but landed asymmetrically because of a sloped landing surface. In this condition, sensory feedback provided conflicting information, and only visual feedback could appropriately predict the asymmetrical landing. During the roll treatment, when all sensory feedback could be used to predict an asymmetrical landing, pre-landing forelimb muscle activity and movement began earlier in the limb that landed first. However, no such asymmetries in forelimb preparation were apparent during hops onto sloped landings when only visual information could be used to predict landing asymmetry. These data suggest that toads prioritize vestibular or proprioceptive information over visual feedback to coordinate landing.

Evidence toads may modulate landing preparation without predicting impact time

Within anurans (frogs and toads), cane toads (Bufo marinus) perform particularly controlled landings in which the forelimbs are exclusively used to decelerate and stabilize the body after impact. Here we explore how toads achieve dynamic stability across a wide range of landing conditions. Specifically, we suggest that torques during landing could be reduced by aligning forelimbs with the body's instantaneous velocity vector at impact (impact angle). To test whether toad forelimb orientation varies with landing conditions, we used high-speed video to collect forelimb and body kinematic data from six animals hopping off platforms of different heights (0, 5 and 9 cm). We found that toads do align forelimbs with the impact angle. Further, toads align forelimbs with the instantaneous velocity vector well before landing and then track its changes until touchdown. This suggests that toads may be prepared to land well before they hit the ground rather than preparing for impact at a specific moment, and that they may use a motor control strategy that allows them to perform controlled landings without the need to predict impact time.

The neurobiology of the meibomian glands

This article compiles research regarding the neuroanatomy of the meibomian glands and their associated blood vessels. After a review of meibomian gland morphology and regulation via hormones, a case for innervation is made based on anatomical findings whereby the nerves lack a myelin sheath and Schwann cells. The localization and co-localization of dopamine beta-hydroxylase, tyrosine hydroxylase, neuropeptide Y, vasoactive intestinal polypeptide, calcitonin gene-related peptide, and substance P are explored with emphasis on differences that exist between species. The presence of the various neuropeptides/neurotransmitters adjacent to the meibomian gland versus the vasculature associated with the meibomian gland is documented so that conclusions can be made with regard to direct and indirect effects. Research regarding the presence of receptors and receptor proteins for these neuropeptides is documented. Evidence supporting the influence of certain neurotransmitters and/or neuropeptides on the meibomian gland is given based on research that correlates changes in meibomian gland morphology and/or tear film with changes in neurotransmitter and/or neuropeptide presence. Conclusions are drawn related to direct and indirect regulation and differences between the various nervous systems.

A physical model of the extreme mantis shrimp strike: kinematics and cavitation of Ninjabot

To study the mechanical principles and fluid dynamics of ultrafast power-amplified systems, we built Ninjabot, a physical model of the extremely fast mantis shrimp (Stomatopoda). Ninjabot rotates a to-scale appendage within the environmental conditions and close to the kinematic range of mantis shrimp's rotating strike. Ninjabot is an adjustable mechanism that can repeatedly vary independent properties relevant to fast aquatic motions to help isolate their individual effects. Despite exceeding the kinematics of previously published biomimetic jumpers and reaching speeds in excess of 25 m s(-1) at accelerations of 3.2 × 10(4) m s(-2), Ninjabot can still be outstripped by the fastest mantis shrimp, Gonodactylus smithii, measured for the first time in this study. G. smithii reached 30 m s(-1) at accelerations of 1.5 × 10(5) m s(-2). While mantis shrimp produce cavitation upon impact with their prey, they do not cavitate during the forward portion of their strike despite their extreme speeds. In order to determine how closely to match Ninjabot and mantis shrimp kinematics to capture this cavitation behavior, we used Ninjabot to produce strikes of varying kinematics and to measure cavitation presence or absence. Using Akaike Information Criterion to compare statistical models that correlated cavitation with a variety of kinematic properties, we found that in rotating and accelerating biological conditions, cavitation inception is best explained only by maximum linear velocity.

Everyday ethics and help-seeking in early rheumatoid arthritis

BACKGROUND

Sociological understandings of chronic illness have revealed tensions and complexities around help-seeking. Although ethics underpins healthcare, its application in the area of chronic illness is limited. Here we apply an ethical framework to interview accounts and identify ethical challenges in the early rheumatoid arthritis (RA) experience.

METHODS

In-depth interviews were conducted with eight participants who had been diagnosed with RA in the 12 months prior to recruitment. Applying the concepts of autonomous decision-making and procedural justice highlighted ethical concerns which arose throughout the help-seeking process. Analysis was based on the constant-comparison approach.

RESULTS

Individuals described decision-making, illness actions and the medical encounter. The process was complicated by inadequate knowledge about symptoms, common-sense understandings about the GP appointment, difficulties concerning access to specialists, and patient-practitioner interactions. Autonomous decision-making and procedural justice were compromised. The accounts revealed contradictions between the policy ideals of active self-management, patient-centred care and shared decision-making, and the everyday experiences of individuals.

CONCLUSIONS

For ethical healthcare there is a need for: public knowledge about early RA symptoms; more effective patient-practitioner communication; and increased support during the wait between primary and secondary care. Healthcare facilities and the government may consider different models to deliver services to people requiring rheumatology consults.

Discrete solitons in electromechanical resonators

We consider a particular type of parametrically driven discrete Klein-Gordon system describing microdevices and nanodevices, with integrated electrical and mechanical functionality. Using a multiscale expansion method we reduce the system to a discrete nonlinear Schrödinger equation. Analytical and numerical calculations are performed to determine the existence and stability of fundamental bright and dark discrete solitons admitted by the Klein-Gordon system through the discrete Schrödinger equation. We show that a parametric driving can not only destabilize onsite bright solitons, but also stabilize intersite bright discrete solitons and onsite and intersite dark solitons. Most importantly, we show that there is a range of values of the driving coefficient for which dark solitons are stable, for any value of the coupling constant, i.e., oscillatory instabilities are totally suppressed. Stability windows of all the fundamental solitons are presented and approximations to the onset of instability are derived using perturbation theory, with accompanying numerical results. Numerical integrations of the Klein-Gordon equation are performed, confirming the relevance of our analysis.

Pattern formation in the damped Nikolaevskiy equation

The Nikolaevskiy equation has been proposed as a model for seismic waves, electroconvection, and weak turbulence; we show that it can also be used to model transverse instabilities of fronts. This equation possesses a large-scale "Goldstone" mode that significantly influences the stability of spatially periodic steady solutions; indeed, all such solutions are unstable at onset, and the equation exhibits spatiotemporal chaos. In many applications, a weak damping of this neutral mode will be present, and we study the influence of this damping on solutions to the Nikolaevskiy equation. We examine the transition to the usual Eckhaus instability as the damping of the large-scale mode is increased, through numerical calculation and weakly nonlinear analysis. The latter is accomplished using asymptotically consistent systems of coupled amplitude equations. We find that there is a critical value of the damping below which (for a given value of the supercriticality parameter) all periodic steady states are unstable. The last solutions to lose stability lie in a cusp close to the left-hand side of the marginal stability curve.

Assessing risk assessment: genetic testing and screening for complex disease

This paper reports on the presentations from the second session of a 2-day workshop on genetic diversity and science communication, organized by the Institute of Genetics. The four talks in this session (by Sarah Cunningham-Burley, Gail Geller, Michael Hayden, and Theresa Marteau) focused on the topic of risk assessment in the context of genetic testing, screening and preventive medicine for complex disease. Each talk underscored the urgency and importance of evaluating when and for whom risk assessment may be useful. A recurrent theme was the need to attend closely to the diverse ways that risk is constructed, perceived and communicated in a variety of contexts and the significant implications of this for laypersons as well as experts. Although there was no consensus on when genetic risk assessment ceases (or might begin) to be useful, ensuing dialogue between presenters and participants reflected what is perhaps a new and critical engagement with how risk assessment itself is assessed. In response to this impetus, I use the word RISK as a heuristic to identify, extract and amplify four tendencies that appear to advance understandings of risk assessment towards a more explicitly reflexive, interpretive, and situated form of knowing.

A descriptive model of preventability in maternal morbidity and mortality

OBJECTIVE

To develop a descriptive model of preventability for maternal morbidity and mortality that can be used in quality assurance and morbidity and mortality review processes.

STUDY DESIGN

This descriptive study was part of a larger case-control study conducted at the University of Illinois at Chicago in which maternal deaths were cases and women with severe maternal morbidity served as controls. Morbidities and mortalities were classified by a team of clinicians as preventable or not preventable. Qualitative analysis of data was conducted to identify and categorize different types of preventable events.

RESULTS

Of 237 women, there were 79 women with preventable events attributable to provider or system factors. The most common types of preventable events were inadequate diagnosis/recognition of high-risk (54.4%), treatment (38.0%), and documentation (30.7%).

CONCLUSIONS

A descriptive model was illustrated that can be used to categorize preventable events in maternal morbidity and mortality and can be incorporated into quality assurance and clinical case review to enhance the monitoring of hospital-based obstetric care and to decrease medical error.

Swift-Hohenberg model for magnetoconvection

A model system of partial differential equations in two dimensions is derived from the three-dimensional equations for thermal convection in a horizontal fluid layer in a vertical magnetic field. The model consists of an equation of Swift-Hohenberg type for the amplitude of convection, coupled to an equation for a large-scale mode representing the local strength of the magnetic field. The model facilitates both analytical and numerical studies of magnetoconvection in large domains. In particular, we investigate the phenomenon of flux separation, where the domain divides into regions of strong convection with a weak magnetic field and regions of weak convection with a strong field. Analytical predictions of flux separation based on weakly nonlinear analysis are extended into the fully nonlinear regime through numerical simulations. The results of the model are compared with simulations of the full three-dimensional magnetoconvection problem.

Instability of convection in a fluid layer rotating about an oblique axis

We analyze thermal convection in a fluid layer confined between isothermal horizontal boundaries at which the tangential component of the fluid stress vanishes. The layer rotates about an oblique, nearly vertical axis. Using a model set of equations for w, the horizontal planform of the vertical velocity component, and psi, a stream function related to a large-scale vertical vorticity field, we describe the instabilities of convection rolls. We show how the usual Küppers-Lortz instability, which leads to a continual precession of the roll pattern, can be suppressed by the oblique rotation vector. Of particular interest is the small-angle instability of rolls, to perturbations in the form of rolls that are almost aligned with the primary rolls; at finite Prandtl number, this instability is not prevented by the horizontal component of the rotation vector, unless this component is sufficiently strong, in which case stability is confined to small-amplitude rolls near the marginal stability boundary. A one-dimensional instability leading to amplitude-modulated rolls is unaffected by the oblique rotation. Numerical simulations of the model equations are presented, which illustrate the instabilities analyzed.

Behavior of the reaction front between initially segregated species in a two-stage reaction

The large-time asymptotic behavior of a two-stage reaction (A+B-->R, B+R-->S) with initially segregated reactants is described. The concentration of the reactants is found to be significantly less than the initial concentrations in a depletion zone of width proportional to t(1/2), where t is time; the reaction takes place in a thinner zone of width proportional to t(1/6). Similarity solutions for the chemical concentration profiles in the reaction zone are calculated, and are compared with numerical simulations of the full partial differential reaction-diffusion equations. The large-time asymptotic scalings reported here are the same as in the absence of the secondary reaction, but we find that the location of the reaction zone is significantly shifted due to the secondary reaction. The reaction zone may behave in an exotic fashion at large time, moving first one way, then reversing its direction.

Infection and preterm labor

There are many conditions, such as non-white race, young maternal age, and uterine malformations, that have been associated with preterm birth that are not amenable to intervention. Maternal cervical and intrauterine infection and inflammation may have a primary causative role in a fraction of the cases of preterm birth and preterm rupture of membranes and may also interact adversely with a variety of maternal (shortened cervix, smoking) and fetal factors (polyhydramnios, multifetal gestation) to decrease the threshold to preterm birth. Further studies are needed to better-define the link between various maternal microbial colonizations and preterm delivery, with the possibility to establish new screening and treatment recommendations. Because of the innumerable causes of preterm birth, a new strategy of targeted treatment of cervical or vaginal infections may lead to only a modest reduction in the incidence of this devastating problem of modern obstetrics.

Symptomatic nephrolithiasis complicating pregnancy

OBJECTIVE

To review our experiences with diagnosis and management of symptomatic nephrolithiasis complicating pregnancy and to ascertain the efficacy of renal sonography for initial diagnosis compared with plain x-rays or single-shot intravenous pyelography.

METHODS

Perinatal outcomes were evaluated for all pregnant women admitted to Parkland Hospital for nephrolithiasis from 1986 to 1999. Diagnostic studies and management of nephrolithiasis were also evaluated.

RESULTS

During the 13-year study period, 57 pregnant women had 73 admissions for symptomatic nephrolithiasis. Symptomatic nephrolithiasis complicated 1 in 3300 (0.03%) deliveries at our institution. Only 12 women (20%) had a history of renal calculi. Mean gestational age at diagnosis was 23 weeks. Imaging techniques included renal ultrasonography, plain abdominal x-ray, and single-shot intravenous pyelography. Calculi were visualized in 21 of 35 (60%) renal ultrasonographic examinations and 4 of 7 (57%) abdominal x-ray studies when these were performed as the initial test. In contrast, urolithiasis was discovered in 13 of 14 (93%) instances in which intravenous pyelography was performed as the initial diagnostic test. When sonography was negative (n = 14), renal calculi were confirmed by single-shot intravenous pyelography (n = 8). Although 43 of 57 (75%) of symptomatic episodes responded to conservative management, 10 women required ureteral stents, 3 needed percutaneous nephrostomy tubes, and 2 underwent ureteral laser lithotripsy for resolution.

CONCLUSION

Although the convenience and safety of ultrasonography to initially diagnose nephrolithiasis are indisputable, 40% of calculi were missed when this method alone was used. Thus, if nephrolithiasis is still suspected clinically despite ultrasonographic findings, single-shot pyelography is recommended.

One-dimensional pattern formation with galilean invariance near a stationary bifurcation

One-dimensional pattern formation with Galilean symmetry is not governed by the Ginzburg-Landau equation near onset; an additional equation describing a large-scale mean flow is required. We derive these amplitude equations and predict the solution amplitude. All steady patterns are unstable, with the growth of the instability taking place on a faster time scale than the formation of the pattern itself. Numerical simulations show that chaotic solutions are obtained, whose amplitude is consistent with our theory.

Uterine prolapse associated with bladder exstrophy: surgical management and subsequent pregnancy

Congenital bladder exstrophy affects 1 in 125,000 to 250,000 females. Consisting of absence of the anterior abdominal wall with exposure of the ureteral orifices, failure of pubic symphysis fusion, and deficient anterior pelvic diaphragm musculature, bladder exstrophy is frequently associated with genital prolapse. Pregnancy may be complicated by recurrent urinary tract infections, preterm labor, mild procidentia, and malpresentation. Due to the rarity of the condition, there is a corresponding scarcity of obstetric literature regarding management during pregnancy. We report the case of a young woman with surgically repaired bladder exstrophy who developed genital prolapse. The uterus was suspended using a sacral colpopexy utilizing a Gore-Tex graft. Subsequently, the patient became pregnant and delivered a healthy male infant at 35 weeks' gestation via cesarean section (without recurrence of the genital prolapse postpartum). Sacral colpopexy to correct genital prolapse associated with bladder exstrophy may preserve fertility in young patients.

Attachment behavior and its antecedents in offspring born to methadone-maintained women

Videotaped 35 full-term, African American infants exposed in utero to methadone and 46 comparison infants at 12 months participating in a separation-reunion procedure to assess aspects of the infant's attachment relationship to the mother. Mothers in the two groups were comparable on education, age (18-35 years), socioeconomic status, parity, IQ and marital status. Offspring born to methadone-maintained women did not differ from comparison infants in indexes of proximity-seeking at reunion but did display higher scores on indexes of disorganized and avoidant behavior and lower scores on indexes of contact-maintaining behavior. Mothers' perceptions during pregnancy of their future infants' degree of bothersomeness were also related to higher scores on contact-maintaining behavior and lower scores on avoidant behavior. Finally, antecedents of attachment behavior within the opioid group alone were considered. The implications of using dimensional attachment ratings for uncovering more subtle attachment antecedents are discussed.

Syphilis

Syphilis was first recognized as a distinct syndrome in Europe in the fifteenth century. Despite knowledge of congenital infection for more than 450 years and the existence of adequate therapy for 55 years, congenital infection remains a problem for the practicing clinician. Syphilis is caused by Treponema pallidum. Infection may be transmitted horizontally by sexual contact and vertically as a result of hematogenous dissemination across the placenta. Syphilis is classified as primary, secondary, latent, and tertiary. The diagnosis may be established by darkfield examination of clinical lesions and by serological assays. The drug of choice for syphilis is penicillin. This agent is the only antibiotic of proven value for the treatment of congenital syphilis. Accordingly, infected pregnant women who are allergic to beta-lactam antibiotics must be desensitized and then treated with penicillin.

Clinical chorioamnionitis and the prognosis for very low birth weight infants

OBJECTIVE

To determine the effects of clinical chorioamnionitis on neonatal morbidity and mortality in very low birth weight infants.

METHODS

This was an observational cohort analysis of all singleton live-born infants weighing 500-1500 g at 24 weeks' or greater gestational age and born between 1988 and 1996 at Parkland Memorial Hospital, Dallas, Texas. Chorioamnionitis was diagnosed on the basis of maternal fever of 38C with supporting clinical evidence, which included fetal tachycardia, uterine tenderness, and/or malodorous infant, and the absence of another source of infection. Multiple logistic regression analysis was used to adjust for outcomes of interest.

RESULTS

Ninety-five of 1367 very low birth weight infants (7%) were exposed to chorioamnionitis. Neonatal sepsis, respiratory distress syndrome, seizure in the first 24 hours of life, intraventricular hemorrhage (grade 3 or 4), and periventricular leukomalacia were all significantly increased with chorioamnionitis, after adjusting for preterm ruptured membranes, pregnancy-associated hypertension, cesarean birth, gestational age, and birth weight. The odds ratios for intraventricular hemorrhage, periventricular leukomalacia, and seizures in the first 24 hours were 2.8 (95% confidence interval [CI] 1.6, 4.8), 3.4 (95% CI 1.6, 7.3), and 2.9 (95% CI 1.2, 6.8), respectively.

CONCLUSION

Our results suggest a link between clinical chorioamnionitis and several indices of neonatal morbidity in the very low birth weight infant. Chorioamnionitis appears to make the very low birth weight infant particularly vulnerable to neurologic damage.

The relationship of infection to method of delivery in twin pregnancy

OBJECTIVE

Our purpose was to determine whether manipulation of the second twin increases the risk of postpartum infection.

STUDY DESIGN

Medical records of all twin deliveries between January 1991 and December 1994 were reviewed. The route of delivery (vaginal vs cesarean section) was examined. The vaginal group was further divided into those delivered in the vertex/vertex position (i.e., no uterine manipulation) versus those delivered vertex/breech extraction (i.e., manipulation). The chi 2 and Student t test were used where appropriate.

RESULTS

A total of 718 twins were identified, and maternal age, parity, gestational age at delivery (36 weeks), and birth weight (2278 gm) were similar among groups. The metritis rate was higher in the cesarean group (74/447 or 18%) than in the vaginal group (17/299 or 5.7%, p < 0.001). In comparing the vaginal group delivered without uterine manipulation with the vaginal group delivered with manipulation (i.e., breech extraction), there was no difference in the incidence of metritis (10/147 or 6.8% vs 7/152 or 4.6%, not significant). The length of time between delivery of twin A and twin B did not affect the metritis rate. Neonatal outcomes including sepsis, neonatal death, and length of hospitalization were similar among groups (not significant).

CONCLUSION

Uterine manipulation of the second twin does not increase the risk of postpartum metritis or neonatal sepsis. In addition, the time interval between delivery of twins A and B has no effect on the rate of metritis. Although the rate of endometritis has been reported to be higher with twins delivered by cesarean section compared to singletons, the 18% rate of endometritis in twins delivered by cesarean section in this study is slightly lower than in our general population of cesarean deliveries (22%).

Outcome of twin gestations with a single anomalous fetus

OBJECTIVE

Our goal was to determine whether the presence of one anomalous fetus in a twin gestation affects pregnancy outcome when compared with twin pregnancies without fetal anomalies.

STUDY DESIGN

Maternal and neonatal data from 970 twin pregnancies delivered from 1988 to 1995 were collected. Three groups of twin gestations were identified: one fetus with a major anomaly (n = 18), one fetus with a minor anomaly (n = 38), and both fetuses without anomalies (n = 914).

RESULTS

Maternal demographic characteristics (age, race, and antepartum complications) were similar among the groups. There was no difference in neonatal outcome (gestational age at delivery, birth weight, cord pH, sepsis, and death) in the minor anomaly and no anomaly groups. There were significant differences between the major anomaly group and the no anomaly group in gestational age at delivery (32.9 vs 35.6 weeks, p < 0.05), birth weight at delivery (1759 vs 2291 gm, p < 0.05), hospital days (41 vs 13 days, p < 0.05), and perinatal death of the anomalous fetus (278/1000 vs 10/1000). Except for total days in the hospital, there was no difference in neonatal morbidity or mortality for the normal fetus when compared with the minor group or the no anomaly group.

CONCLUSION

The presence of a fetus with a major anomaly in a twin gestation increases the risk of preterm delivery. The neonatal outcome of the nonanomalous fetus does not appear to be affected by the anomalous fetus.

Accumulation of interleukin-1beta and interleukin-6 in amniotic fluid: a sequela of labour at term and preterm

From the finding of micro-organisms or inflammatory mediators, or both, in amniotic fluid (AF), it has been proposed that intrauterine infection is one cause of preterm labour (PTL, intact fetal membranes). This theory, however, remains unproved, i.e. the accumulation of micro-organisms and inflammatory mediators in AF after labour is in progress may be the consequence, not the cause, of labour both at term and preterm. This study was conducted to evaluate this possibility by a comparison of the concentrations of interleukin (IL)-1beta and IL-6 in AFs collected before and during PTL (<34 weeks gestation) with those in AFs collected at term (before labour and from the forebag and upper compartments of the amniotic sac during labour). The concentrations of IL-1beta and IL-6 in AF were also analysed as a function of the duration of labour (term or preterm) before fluid collection. In addition, studies were conducted to define the source of IL-1beta in AF. A total of 666 AFs were evaluated. IL-1beta was not detected (<50 pg/ml) in AFs collected before the onset of labour at any stage of gestation (n = 320), including 170 fluids obtained at term. During labour, IL-1beta was detected (>50 pg/ml) in 58 out of 106 (54.7%), 17 out of 64 (26.6%) and 60 out of 176 (34%) of AF samples obtained during PTL, term labour (upper compartment) and term labour (forebag) respectively. AF sampling, as well as labour and delivery, were completed in <18 h in all term pregnancies. However, labour (with cervical dilation) was in progress for >18 h before AF was collected in 39 out of 106 (37%) PTL pregnancies. The incidence of IL-1beta-positive samples among AFs collected before 18 h of PTL (23 out of 67; 34%) was indistinguishable from that in AFs collected during labour at term. However, in AFs collected after >18 h PTL, the incidence of IL-1beta-positive samples was 35 out of 39 (89.7%) The concentrations of IL-1beta (pg/ml; mean +/- SEM) in AFs collected during PTL (2680 +/- 730; n = 106) were greater than those in AFs collected from the upper compartment and forebag during term labour (436 +/- 244, n = 64; and 468 +/- 119, n = 176) respectively; this difference, however, was attributable to very high concentrations of IL-1beta in AFs in which PTL was in progress for >18 h before AF collection (6021 +/- 1832; n = 39). The concentrations of IL-6 in AF were correlated with those of IL-1beta (P < 0.001). We conclude that IL-1beta and IL-6 accumulate in AF in a similar proportion of pregnancies during the first 18 h of term and preterm labour. Therefore, the accumulation of these cytokines in AF cannot be taken as evidence for a role for infection in the pathogenesis of PTL.

Postcesarean analgesia with both epidural morphine and intravenous patient-controlled analgesia: neurobehavioral outcomes among nursing neonates

Among nursing parturients after cesarean delivery, intravenous patient-controlled analgesia (PCA) with meperidine is associated with significantly more neonatal neurobehavioral depression than PCA with morphine. A single dose of epidural morphine (4 mg) decreases postcesarean opioid analgesic requirements and may reduce or prevent neonatal neurobehavioral depression associated with PCA meperidine. Prospectively, 102 term parturients underwent cesarean delivery with epidural anesthesia, 2% lidocaine and epinephrine 1:200,000. After umbilical cord clamping, each patient received epidural morphine 4 mg and was randomly allocated to receive either PCA meperidine or PCA morphine. Initial neonatal characteristics, included gestational age, Apgar scores, weight, and umbilical cord gas partial pressures. Brazelton Neonatal Behavioral Assessment Scale (NBAS) examinations were performed on each of the first 4 days of life. Nursing infants (n = 47) were grouped according to maternal PCA opioid in breast milk (meperidine [n = 24] or morphine [n = 23]); bottle-fed infants (n = 56) served as the control group. The three infant groups were equivalent with respect to initial characteristics and NBAS scores on the first 2 days of life. On the third day of life, infants in the morphine group were significantly more alert and oriented to animate human cues compared with infants in the meperidine or control group. On the fourth day of life, infants in the morphine group remained significantly more alert and oriented to animate human auditory cues than infants in the meperidine group. Average PCA opioid consumption through 48 h postpartum was equivalent (0.54 mg/kg morphine and 4.7 mg/kg meperidine); however, even with these small doses, meperidine was associated with significantly poorer neonatal alertness and orientation than morphine. Morphine is the PCA opioid of choice for postcesarean analgesia among nursing parturients.

IMPLICATIONS

Among nursing parturients after cesarean delivery, intravenous patient-controlled analgesia with meperidine is associated with more neonatal neurobehavioral depression than patient-controlled analgesia with morphine. In this study, we found that nursing infants exposed to morphine were more alert and oriented to animate human cues than those exposed to meperidine.

Urinary tract infections complicating pregnancy

Urinary tract infections (asymptomatic bacteriuria, cystitis, and pyelonephritis) are frequently encountered medical complications of pregnancy. The majority of infections in pregnancy are asymptomatic; however, even covert bacteriuria places the mother at risk for low birth weight and preterm birth. Pyelonephritis can result in significant maternal and fetal morbidity and mortality. Therefore, all pregnant women should be screened for asymptomatic bacteriuria, and urinary tract infections should be promptly treated to prevent adverse pregnancy outcome. This article reviews the diagnosis, etiology, treatment, and complications associated with urinary tract infections in pregnancy.

Chorioamnionitis and endometritis

Chorioamnionitis complicates 1% to 2% of all pregnancies and may affect 10% of women with certain risk factors. Intraamnionic infection may result in devastating morbidity for both the fetus and the mother. Also, chorioamnionitis is associated with higher cesarean section rates. As demonstrated earlier, endometritis is a common complication of cesarean delivery alone. Nevertheless, antibiotic prophylaxis has been shown to reduce postpartum morbidity. In the face of chorioamnionitis and a cesarean delivery, the risk of developing endometritis increases exponentially. However, if appropriate antibiotic therapy is instituted at the time of diagnosis, fetal and maternal outcomes improve dramatically. Similar to chorioamnionitis, endometritis is usually polymicrobial in nature. The preponderance of the organisms isolated are anaerobic. Established risk factors include operative delivery, prolonged ruptured fetal membranes, and prolonged labor. The diagnosis is based primarily on clinical examination with fever and the exclusion of other sources of extrapelvic infection. Once the diagnosis is established, appropriate empiric antibiotics are instituted. Antibiotic therapy should be continued until the patient is afebrile and asymptomatic for 24 to 36 hours. Over the past 20 years, the use of single-agent therapy in these serious infections has been shown to be safe as well as effective. Once successful therapy is completed, the patient is discharged home with no oral antibiotics.

Ampicillin for neonatal group B streptococcal prophylaxis: how rapidly can bactericidal concentrations be achieved?

OBJECTIVE

Our purpose was to determine how rapidly bactericidal concentrations of ampicillin against group B streptococci are achieved in amniotic fluid and cord blood after a 2 gm maternal infusion.

STUDY DESIGN

Ampicillin was administered at varying time intervals between 3 and 67 minutes before elective cesarean delivery in 40 women. Samples of amniotic fluid were obtained by amniocentesis just before the uterine incision was made. Umbilical and maternal blood were obtained at the time of delivery. Ampicillin concentrations were measured by high-pressure liquid chromatography.

RESULTS

The mean concentrations of ampicillin measured in maternal and umbilical cord sera all exceeded the minimum bactericidal concentrations reported for group B streptococci (0.25 to 2.0 micrograms/ml) and were achieved as soon as 5 minutes after ampicillin infusion. Similarly, bactericidal levels of ampicillin in the amniotic fluid could be detected as early as 5 minutes. However, such concentrations of ampicillin in the amniotic fluid were achieved in only 85% of the pregnancies studied.

CONCLUSIONS

Bactericidal levels of ampicillin against group B streptococci can usually be achieved rapidly in both fetal blood and amniotic fluid after a standard 2 gm intravenous dose given to the mother for neonatal prophylaxis.

Clinical course of premature rupture of the membranes

Premature rupture of the membranes (PROM), defined as rupture of the membranes before the onset of labor, is a common obstetric event occurring in 10% of pregnancies. Most of the time this occurs at or beyond 37 weeks' gestation with only 10% of PROM occurring at less than 37 weeks' gestation. The natural course of PROM is labor, and at term this is associated with a low rate of complications for the mother and the fetus. At less than 37 weeks' gestation PROM places the mother and the fetus at increased risk of short-term and long-term morbidity and mortality. Several factors related to preterm premature rupture of the membranes (PROM) add risk to the pregnancy and include premature delivery, infection in the mother and the fetus, effects of prolonged oligohydramnios on fetal development, abruptio placenta, prolapsed cord, and fetal malposition. Since the 1970s expectant management has been the standard treatment for PROM; however, in the majority of patients, this strategy results in the delivery of a preterm infant. In addition, controversy exists over the gestational age at which expectant management should be abandoned and active interventions to effect delivery pursued. This article discusses the natural history of PROM, the outcome of expectant management in PROM, and maternal and fetal outcomes in these patients. The emphasis of this discussion is on the preterm fetus.

Randomized investigation of antimicrobials for the prevention of preterm birth

OBJECTIVE

Occult amniotic fluid infection has emerged as a possible cause of many heretofore unexplained preterm births. We sought to determine whether antimicrobial therapy is effective in preventing preterm delivery.

STUDY DESIGN

A double-blind, placebo-controlled, randomized trial was conducted to study the efficacy of ampicillin-sulbactam and amoxicillin-clavulanic acid in women hospitalized for preterm labor between 24 and 34 weeks' gestation. During this investigation no tocolytics or steroids were used.

RESULTS

Thirty-nine women with preterm labor received antimicrobial therapy and 39 received placebos. The mean gestational ages at study entry were 29.8 +/- 0.4 weeks (SEM) and 30.6 +/- 0.3 weeks in the antimicrobial and placebo groups, respectively (not significant). Similarly, the mean gestational ages at delivery were 34.2 +/- 0.7 and 34.1 +/- 0.6 weeks, respectively (not significant). Other index values of pregnancy outcome, for example, birth weight, neonatal morbidity, and prenatal death, were not significantly improved by antimicrobial therapy given to the mother in preterm labor.

CONCLUSION

We find that antimicrobial therapy given to women in preterm labor is ineffective in the prevention of preterm birth.

Intentional delivery versus expectant management with preterm ruptured membranes at 30-34 weeks' gestation

OBJECTIVE

To determine maternal and neonatal outcomes in pregnancies complicated by preterm rupture of membranes (PROM) at 30-34 weeks' gestation.

METHODS

A randomized controlled trial was conducted to study the benefits of expectant management in women hospitalized for PROM at 30-34 weeks' gestation. During this investigation, no tocolytics, corticosteroids, or prophylactic antibiotics were used.

RESULTS

Sixty-eight women with PROM were managed expectantly and 61 were delivered intentionally. The mean gestational age at study entry was 31.7 weeks in both the expectant management and intentional delivery groups (P > .05). The mean gestational ages at delivery were similar (32.0 and 31.7 weeks, respectively). Other indices of pregnancy outcome (ie, birth weight, intraventricular hemorrhage, necrotizing enterocolitis, sepsis, respiratory distress syndrome, and perinatal death) were not significantly improved by expectant management. However, there was a significant increase in the incidence of chorioamnionitis and antepartum hospitalization in the women managed expectantly.

CONCLUSION

There were no clinically significant neonatal advantages to expectant management of ruptured membranes at 30-34 weeks. Antepartum hospitalization was decreased by 2.5 days in those women randomized to intentional delivery.

Emergent obstetric management of uterine inversion

Puerperal inversion of the uterus is an unusual and potentially life-threatening event occurring in the third stage of labor, but when managed promptly and aggressively inversion can result in minimal maternal morbidity and mortality. Once the diagnosis of inversion is made, measures should be undertaken to manage and correct acute blood loss and potential shock. In conjunction with anesthesia personnel, immediate uterine replacement should be considered. Uterine relaxants (MgSO4, terbutaline, or halothane) can be used if initial attempts fail; however, in the majority of patients successful immediate replacement without use of uterine relaxants is possible. The choice of anesthetic agent and uterine relaxants should be individualized based on the clinical scenario. Following manual replacement, massage and ecbolic agent(s) should be instituted immediately to prevent reinversion. Surgical repositioning via an abdominal or vaginal approach may be necessary in subacute or chronic inversions.

The correlation between transperineal sonography and digital examination in the evaluation of the third-trimester cervix

OBJECTIVE

To determine the correlation between transperineal or translabial ultrasound and digital examination of the cervix in the third trimester in women presenting to the obstetrical triage area complaining of uterine contractions and/or rupture of membranes.

METHOD

One hundred women were evaluated initially with an ultrasound unit using a 5-MHz glove-covered curvilinear transducer applied to the perineum in the sagittal plane. Immediately after the ultrasound evaluation, another examiner assessed the cervix digitally, blinded to the sonographic results. Cervical dilatation, length, and station were assessed.

RESULTS

Transperineal ultrasound correlated (P < .001) with digital cervical examination in the assessment of dilatation (Pearson correlation coefficient 0.87), length (Pearson correlation coefficient 0.80), and corrected station (Pearson correlation coefficient 0.69).

CONCLUSION

There is a statistically significant correlation between the digital cervical examination and the sonographic assessment of cervical dilatation, length, and station by the transperineal approach.

Coarctation of the abdominal aorta in pregnancy: diagnosis by magnetic resonance imaging

BACKGROUND

Coarctation of the aorta is rare, affecting one per 2000-3000 women. Abdominal coarctation is more commonly identified in women than in men, but only two cases have been reported in pregnancy.

CASE

A 26-year-old woman was diagnosed with hypertension at 15 years of age. Her blood pressure was controlled adequately with beta-blockers. During her pregnancy, she was found to have coarctation of the abdominal aorta by magnetic resonance imaging.

CONCLUSION

Magnetic resonance imaging is a safe, reliable means by which to confirm clinically suspected coarctation of the aorta during pregnancy.

Genital herpes during pregnancy: no lesions, no cesarean

OBJECTIVE

To determine the effects at our hospital of adoption of the 1988 guidelines recommended by ACOG for management of genital herpes infections during pregnancy.

METHODS

Between 1984-1986, 96 pregnancies complicated by active genital herpes were delivered at Parkland Hospital. The outcome of these pregnancies were compared with 217 similar pregnancies managed after implementation of the 1988 ACOG herpes guidelines.

RESULTS

Adoption of the 1988 ACOG herpes guidelines resulted in a 37% decrease in the use of cesarean delivery for women with genital herpes infections at our hospital. Most of this decrease was because the new guidelines eliminated the need for a confirmatory negative herpes culture before permitting vaginal delivery. No neonatal herpes infections occurred as a result of implementing the ACOG recommendations.

CONCLUSION

The rate of cesarean delivery for women with genital herpes infections during pregnancy declined significantly at our hospital as a result of the adoption of ACOG herpes guidelines, and there were no neonatal consequences, such as increased incidence of neonatal herpes simplex virus infection.

Assessment of the resident in-training examination in obstetrics and gynecology

An integral component for the evaluation of resident's cognitive knowledge is the examination developed under the auspices of the Council on Resident Education in Obstetrics and Gynecology (CREOG). We sought to assess the usefulness of this annual examination from the perspective of both residents and residency program directors. We were particularly interested in comparing the contemporary use of this examination with the original intent of CREOG when the examination was developed in 1968. In addition, we were interested in determining the role of the examination in modifying educational programs. A questionnaire was mailed to all program directors before the 1994 examination and given to all house staff when the examination was administered. The response rate was 55 and 82%, respectively. Overall, the majority of residents (60%) and program directors (58%) found the examination to be an accurate assessment of cognitive knowledge; feedback on examination results varied widely, and residents used a variety of tools to prepare for the examination.