Gestational glyphosate exposure and early childhood neurodevelopment in a Puerto Rico birth cohort

INTRODUCTION

N-(phosphonomethyl)glycine, or glyphosate, is a non-selective systemic herbicide widely used in agricultural, industrial, and residential settings since 1974. Glyphosate exposure has been inconsistently linked to neurotoxicity in animals, and studies of effects of gestational exposure among humans are scarce. In this study we investigated relationships between prenatal urinary glyphosate analytes and early childhood neurodevelopment.

METHODS

Mother-child pairs from the PROTECT-CRECE birth cohort in Puerto Rico with measures for both maternal urinary glyphosate analytes and child neurodevelopment were included for analysis (n = 143). Spot urine samples were collected 1-3 times throughout pregnancy and analyzed for glyphosate and aminomethylphosphonic acid (AMPA), an environmental degradant of glyphosate. Child neurodevelopment was assessed at 6, 12, and 24 months using the Battelle Developmental Inventory, 2nd edition Spanish (BDI-2), which provides scores for adaptive, personal-social, communication, motor, and cognitive domains. We used multivariable linear regression to examine associations between the geometric mean of maternal urinary glyphosate analytes across pregnancy and BDI-2 scores at each follow-up. Results were expressed as percent change in BDI-2 score per interquartile range increase in exposure.

RESULTS

Prenatal AMPA concentrations were negatively associated with communication domain at 12 months (%change = -5.32; 95%CI: 9.04, -1.61; p = 0.007), and communication subdomain scores at 12 and 24 months. At 24 months, four BDI-2 domains were associated with AMPA: adaptive (%change = -3.15; 95%CI: 6.05, -0.25; p = 0.038), personal-social (%change = -4.37; 95%CI: 7.48, -1.26; p = 0.008), communication (%change = -7.00; 95%CI: 11.75, -2.26; p = 0.005), and cognitive (%change = -4.02; 95%CI: 6.72, -1.32; p = 0.005). Similar trends were observed with GLY concentrations, but most confidence intervals include zero. We found no significant associations at 6 months.

CONCLUSIONS

Our results suggest that gestational exposure to glyphosate is associated with adverse early neurodevelopment, with more pronounced delays at 24 months. Given glyphosate's wide usage, further investigation into the impact of gestational glyphosate exposure on neurodevelopment is warranted.

Breath stacking in children with neuromuscular disorders

Respiratory muscle weakness in neuromuscular disorders (NMD) can lead to shallow breathing and respiratory insufficiency over time. Children with NMD often cannot perform maneuvers to recruit lung volume. In adults, breath stacking with a mask and one-way valve can achieve significantly increased lung volumes. To evaluate involuntary breath stacking (IBS) in NMD, we studied 23 children of whom 15 were cognitively aware and able to communicate verbally. For IBS, a one-way valve and pneumotachograph were attached to a face mask. Tidal volumes (Vt) and minute ventilation (VE ) were calculated from airflow over 30 sec before and after 15 sec of expiratory valve closure. Six cooperative male subjects with Duchenne muscular dystrophy (DMD) participated in a subsequent comparison of IBS with voluntary breath stacking (VBS) and supported breath stacking (SBS). The average Vt in those studied with IBS was 277 ml (range 29-598 ml). The average increase in volume by stacking was 599 ml (range -140 to 2,916 ml) above Vt . The average number of stacked breaths was 4.5 (range 0-17). VE increased on average by 18% after stacking (P < 0.05, paired t-test). Oxygen saturation did not change after stacking. Four of the 23 children did not breath stack. Compared to IBS, VBS achieved similar volumes in the six subjects with DMD but SBS was more successful in those with greatest muscle weakness. IBS may achieve breath volumes of approximately three times Vt and may be particularly useful in non-cooperative subjects with milder degrees of respiratory muscle weakness.

Observing stimulus sources that signal food or no food

Pigeons were given a choice between observing a stimulus source that was uncorrelated with food or one that was informative. The informative source was either positive, in which a stimulus change signalled food, or negative, in which change signalled no food. If observing is supported by the reduction of uncertainty, the negative as well as the positive source should be preferred to the uncorrelated source. On the other hand, if observing requires support by conditioned reinforcement, the negative source should not be preferred to the uncorrelated source. Two keys served as stimulus sources in a discrete trial procedure. The keys were lighted together, remained on for a variable length of time, and went off together. A key could change color 1 sec before going off. In the uncorrelated source, the change occurred equally often on trials ending with or without food. In the positive information source, the change occurred only on food trials, whereas in the negative information source, it occurred only on no-food trials. All stimulus changes and food delivery were response independent. As measured by orientation and autoshaped pecking, the positive information source was preferred to the uncorrelated source. However, the uncorrelated source was preferred to the negative information source. The latter result does not support the view that observing behavior is reinforced by the reduction of uncertainty. The positive and negative information sources reduced uncertainty equally but only the positive source provided a signal that could act as a conditioned reinforcer by virtue of its relation to food.

A randomized single-blind evaluation of a discharge teaching book for pediatric patients with burns

To evaluate the influence of a modular, multidisciplinary, pediatric burn discharge book on burn-care-related knowledge and satisfaction of caregivers, we studied children less than 17 years of age admitted with an acute thermal injury to the pediatric burn unit of a large, tertiary care hospital in Winnipeg, Canada over a 32 month period. Demographic characteristics of the population are similar to published profiles of other pediatric burn units with the exception that North American Indian (NAI) families were disproportionately admitted, with 59 out of the 123 (48%) admissions from a geographic area that has less than 15% NAIs. We randomly assigned the families to receive discharge instructions with the book (intervention group) or routine discharge teaching without the book (comparison group). Knowledge levels of burn care and satisfaction with discharge teaching of caregivers were evaluated with a questionnaire administered in single-blind fashion at the first outpatient follow-up visit. Sixty-two families received the book and 61 families received standard discharge teaching. Bivariate analysis showed greater knowledge in the intervention group, with an average score (range, 0.0 to 1.0) of 0.79 +/- 0.15 versus 0.73 +/- 0.15 in the comparison group (p < 0.05). We did not observe this positive effect of the book when we analyzed NAI families separately: 28 families instructed with the book scored 0.68 +/- 0.14 versus 0.63 +/- 0.13 in 31 families provided with routine teaching (p = 0.18). Stepwise multiple-regression analysis found that the influence of the book was limited to families with children who sustained scald burns (p < 0.05). Factors negatively related to the knowledge levels of caregivers (p < 0.05) were being of NAI origin and being NAI with no safety devices in the home. A positive correlation (p < 0.05) was found with having English as the first language, having a child with more extensive burns, having a younger age of the child with burns, and having fewer children in the home. In conclusion, we found that the discharge book improved the burn-care-related knowledge of caregivers. However, other factors, particularly ethnic and language background, were of greater influence.

A survey of pediatric discharge educational programs in North American burn units

In this study we contacted all of the 149 major North American burn facilities that treat children. The survey determined topics covered in discharge teaching, personnel administering the programs, methods used, and obstacles encountered. The subjects addressed and the personnel involved have changed little from a decade ago. Unfortunately, one fourth of the centers still do not deal with emotional aspects of burns in their discharge programs. For program delivery, videotape is becoming an increasingly accepted teaching method. Eighty-five percent of burn facilities experienced barriers to patient education at discharge, with more than half reporting three or more difficulties. The most common difficulty was time constraints (50%), followed by language and sociocultural barriers (41%), lack of receptivity by clientele (39%), lack of educational materials and planning (26%), and inadequate funding (25%). Some of these problems might be alleviated by the establishment of a clearinghouse for burn educational materials.

Ethical dimensions of leadership in community health nursing

This article deals with ethical leadership. Community health nurse (CHN) leaders are confronted with ethical problems in increasing numbers and complexity. To deal successfully with these dilemmas, nurse leaders must be aware of leadership qualities, know the ethical obligations of leaders, and use actions that produce the best decisions in tough financial times. The main purpose of the article is to present several helpful strategies for CHN leaders to use for ethical decision making. Types of ethical decisions that nurse leaders make are given. Six recommendations for action to be taken for ethical decisions in today's changing health-care climate are explored.

Technical progress in fetal electrocardiography--a review

The fetal electrocardiogram (FECG) was first demonstrated 80 years ago, but initial progress in research into the subject was slow and limited by the technical equipment available. As improved amplifiers became available, the detection of the waveform became easier, but observation of waveform morphology was still difficult because of background noise. The signal-to-noise ratio of the original FECG waveform was improved considerably with the use of directly applied fetal electrodes, and the development of digital computer techniques has allowed signal enhancement. It is now possible to monitor the FECG waveform continuously in labor and reliably produce waveforms with all of the components clearly defined.

Can fetal electrocardiography improve the prediction of intrapartum fetal acidosis?

An outline is given of a computer-based system which continuously enhances and measures the waveform of the intrapartum fetal electrocardiogram. This system has been used to examine the behaviour of the ST segment and T wave in a group of 14 fetuses where the outcome was biochemically and clinically normal, and in a group of 10 fetuses which were acidotic at birth. When the mean values in each group were compared, highly significant differences were found for both of these components of the waveform. These differences have also been demonstrated by the analysis of long-term trends in the behaviour of these variables. The highly significant correlation between both a long-term increase in ST segment and T wave height and fetal acidosis, found in this study, reflects earlier work by others in the experimental animal fetus. The findings suggest that continuous monitoring of the waveform of the fetal electrocardiogram in labour may give a much better prediction of fetal acidosis than is currently achieved with the monitoring of heart rate alone.

Improving clinical decision making in nursing

This article describes the need for effective clinical decision making among nurses. The author believes that responses to the need should begin at the educational level, and offers some thoughts to nurse educators for improvement. Exploring the theory base for decision making with students and coordinating teaching-learning strategies with real opportunities in clinical settings are some of the suggestions made. Nurse educators are urged to encourage competency in decision making and to become role models for others.

Fetal death immediately following normal antenatal fetal heart rate pattern. Case report

A fetal death occurred during antenatal non-stressed cardiotocography in a woman with gestational diabetes. The death occurred immediately following 30 minutes of normal fetal heart rate tracing with an active baby and with normal biochemical tests of placental function.

Responses eliminated by noncontingent or negatively contingent reinforcement recover in extinction

Autoshaped key pecking in pigeons was eliminated by presenting reinforcers only during non-CS periods (negatively contingent reinforcement) or in both non-CS and CS periods (noncontingent reinforcement). In either case, when all reinforcers were subsequently removed (simple extinction), responding recovered strongly (Experiment 1). Recovery in extinction occurred only if the CS was in a conditioned state when non-CS reinforcers were introduced (Experiment 2). Recovery from noncontingent reinforcement was virtually complete, since total responding in extinction after response elimination was not less than in control groups extinguished without an intervening response-elimination phase (Experiment 3). Recovery also occurred for nonautoshapable, instrumentally reinforced key pecking (Experiment 4). The hypothesis that recovery is due to reinstatement of the non-CS stimulus conditions of acquisition (absence of food) was not supported (Experiments 5 and 6). Other accounts of recovery are considered.

The normal condition of the fetal electrocardiogram during labour

A real-time computer system was employed to monitor continuously the fetal electrocardiogram (ECG) during labour. Signals from a scalp electrode were amplified, filtered and passed through an interface system to a digital computer. From 110 patients studied, 37 were selected by rigid criteria which fulfilled a strict definition of normal fetal condition in labour and delivery. The mean values and the range of the various parameters of the fetal ECG complex were defined. As a large amount of data was generated by the system, a method was developed to display the short and long-term dynamic behaviour of the fetal ECG during labour in the form of labour profiles. By further averaging of these labour profiles, the pattern of normal behaviour was established. Certain changes in the fetal ECG, previously thought to be characteristic of fetal distress, occurred in normal patients. The P-R interval was up to 10 per cent shorter during contractions towards the end of labour and there was a long-term trend towards the end of labour for the P-R interval to fall by 7 per cent. The P wave amplitude fell by 30 per cent over the last hour. These trends were statistically significant. The QRS complex was found to lengthen slightly towards the end of labour, but the R-T interval and ST segment displacement displayed no significant changes.

Self concept and mastectomy

The body image and self-concept in two groups of women is described with the use of the Tennessee Self-Concept Scale (TSCS). Twenty-three women 40--60 years of age having unilateral mastectomies within the preceeding 46-month period, volunteered to be tested. Women without mastectomies but similar in age and socioeconomic status formed a comparison sample of 23. No significant differences in self-concept or body image were found between the two groups. The paired sample (study and comparison groups) was noted to be similar to TSCS elderly profiles for these subscales. It was suggested that self-concept and body image, whether one had undergone mastectomy or not, probably is fairly stable at this time in life for women.

The form of the auto-shaped response with food or water reinforcers

The relation between the form of auto-shaped responses to the lighting of a key and the consummatory responses of pecking grain and drinking water was examined in pigeons. Responses on the key were analyzed by means of high-speed photography, recordings of the force of contact, and judges' ratings of response-form based on film and videotape recordings. The first experiment showed that food-deprived birds presented grain as a reinforcer responded on the key with a grain-pecking movement, while water-deprived birds presented water as a reinforcer responded with drinking-like movements. The second and third experiments showed that the resemblance between auto-shaped and consummatory responses does not require the dominance of the deprivational state appropriate to the reinforcer. Changing the dominant state of deprivation did not immediately change the form of the key response, and in subjects simultaneously deprived of food and water, the form of response depended on the reinforcer. In the fourth and fifth experiments, subjects simultaneously deprived of food and water received one stimulus signalling food and another signalling water in a random series. In most subjects, the response to each stimulus resembled the consummatory response to the particular reinforcer that was signalled by the stimulus. This result demonstrates the role of association between a stimulus and a reinforcer in producing a resemblance of the auto-shaped response to the consummatory response.

Auto-shaping of the pigeon's key-peck

Reliable acquisition of the pigeon's key-peck response resulted from repeated unconditional (response-independent) presentations of food after the response key was illuminated momentarily. Comparison groups showed that acquisition was dependent upon light-food pairings, in that order.