High rates of International Code violations: a cross-sectional study in a region of Canada with low breastfeeding rates

BACKGROUND

Exposure to marketing and promotion of commercial milk formula is associated with an increased likelihood of formula-feeding. In 1981, the International Code (IC) of Marketing of Breastmilk Substitutes was adopted by the 34th World Health Assembly to restrict the promotion, marketing and advertising of commercial milk formula and protect breastfeeding.

RESEARCH AIM

The current study examines mothers' exposure to violations of the IC in Newfoundland and Labrador, a province of Canada with low breastfeeding rates.

METHODS

A cross-sectional online survey measured exposure to IC violations (e.g., marketing, advertising and promotion of commercial milk formula) by mothers of infants less than two years old (n = 119). Data were collected on type, frequency, and location of violation.

RESULTS

Most participants (87%, n = 104/119) reported exposure to at least one IC violation. Of this group (n = 104): 94% received coupons or discount codes for the purchase of commercial milk formula; 88% received free samples of commercial milk formula from manufacturers, and 79% were contacted directly by commercial milk formula companies via email, text message, mail or phone for advertising purposes. One-third (n = 28/104, 27%) observed commercial milk formula promotional materials in health care facilities. The most frequent locations were violations occurred were doctors' offices (79%), supermarkets(75%), and pharmacies (71%).

CONCLUSION

The majority of mothers of young infants were exposed to violations of the IC involving the marketing, advertising and promotion of commercial milk formula. Companies producing commercial milk formula reached out directly to new mothers to offer unsolicited promotions and free samples of commercial milk formula.

Transportation, childcare, lodging, and meals: Key for participant engagement and inclusion of historically underrepresented populations in the healthy brain and child development birth cohort

Introduction

Participant recruitment and retention (R&R) are well-documented challenges in longitudinal studies, especially those involving populations historically underrepresented in research and vulnerable groups (e.g., pregnant people or young children and their families), as is the focus of the HEALthy Brain and Child Development (HBCD) birth cohort study. Subpar access to transportation, overnight lodging, childcare, or meals can compromise R&R; yet, guidance on how to overcome these "logistical barriers" is sparse. This study's goal was to learn about the HBCD sites' plans and develop best practice recommendations for the HBCD consortium for addressing these logistical barriers.

Methods

The HBCD's workgroups developed a survey asking the HBCD sites about their plans for supporting research-related transportation, lodging, childcare, and meals, and about the presence of institutional policies to guide their approach. Descriptive statistics described the quantitative survey data. Qualitative survey responses were brief, not warranting formal qualitative analysis; their content was summarized.

Results

Twenty-eight respondents, representing unique recruitment locations across the U.S., completed the survey. The results indicated substantial heterogeneity across the respondents in their approach toward supporting research-related transportation, lodging, childcare, and meals. Three respondents were aware of institutional policies guiding research-related transportation (10.7%) or childcare (10.7%).

Conclusions

This study highlighted heterogeneity in approaches and scarcity of institutional policies regarding research-related transportation, lodging, childcare, and meals, underscoring the need for guidance in this area to ensure equitable support of participant R&R across different settings and populations, so that participants are representative of the larger community, and increase research result validity and generalizability.

Retrospective review of rates of sexually transmitted and blood-borne infection (STBBI) testing in provincial corrections facilities in Newfoundland and Labrador

Background

Sexually transmitted and blood borne infection (STBBI) testing is recommended for people who are incarcerated (PWAI). We sought to determine the rate of STBBI testing during admissions to provincial correctional institutions in Newfoundland and Labrador (NL).

Methods

This retrospective cohort study collected the identification of all admissions records in provincial correctional facilities in NL between July 1, 2020 and June 31, 2021 using the Provincial Corrections Offender Maintenance System database. Admissions to provincial detention centers were excluded. Records were linked with STBBI results, when available, within the electronic medical record (Meditech) using demographics. Testing rates, STBBI positivity rates, and univariate analysis of predictors for STBBI testing were completed.

Results

Of the 1,824 admissions identified, 1,716 were available for linkage to laboratory results. Admissions to detention centers (n = 105) were excluded. Any STBBI test result was available for 72 (4.5%) of admissions. No admission had complete testing for all STBBI. Facility testing rates ranged from 1.9 to 11.2% and 37.5% of STBBI tests had any positive results. Sixteen out of the 21 (76.2%) hepatitis C virus (HCV) antibody positives received HCV RNA testing, and 11/16 (88.8%) were HCV RNA positive. Institution (p = 0.001) and sex (p = 0.004) were found to be significant predictors of STBBI testing, while age was not significant (p = 0.496).

Conclusions

STBBI testing rates were low in provincial correctional facilities in NL, and STBBI prevalence, especially for HCV, was high among those tested. Strategies to increase the rate of testing could contribute to STBBI control in corrections facilities.

A review of the literature: How does prenatal opioid exposure impact placental health and fetal brain development?

In recent years, there has been a sixfold increase in the number of pregnant people with opioid use disorder (OUD). Rates of neonatal opioid withdrawal syndrome (NOWS), previously known as neonatal abstinence syndrome (NAS), have significantly increased in virtually every state and demographic group (Healthcare Cost Utilization Project, HCUP, 2010). NOWS is a condition resulting from chronic exposure to either therapeutic opioid use (e.g., medication for OUD, chronic pain conditions) or nonprescribed opioid use. To date, there is no known prenatal treatment to help decrease the risk of infants developing NOWS and subsequent neurodevelopmental outcomes. Given the increasing support for how placental signaling, or placental programming, may play a role in downstream pathology, prospective research investigating how the placenta is affected by chronic opioid exposure morphologically, histologically, and at the cellular level may open up potential treatment opportunities in this field. In this review, we discuss literature exploring the physiological roles of nitric oxide and dopamine not only in the vascular development of the placenta, but also in fetal cerebral blood flow, neurogenesis, neuronal differentiation, and neuronal activity. We also discuss histological preclinical studies that suggest chronic opioid exposure to induce some combination of placental dysfunction and hypoxia in a manner similar to other well-known placental pathologies, as denoted by the compensatory neovascularization and increased utilization of the placenta's supply of trophoblast cells, which play an essential role in placental angiogenesis. Overall, we found that the current literature, while limited, suggests chronic opioid exposure negatively impacts placental function and fetal brain development on a cellular and histopathological level. We conclude that it is worthwhile to consider the placenta as a therapeutic target with the ultimate goal of decreasing the incidence of NOWS and the long-term impacts of prenatal opioid exposure.

Firefighter Suicide: A Theoretical Model for a Population Specific Behavioral Autopsy Program

Some research suggests that firefighters are possibly at greater risk than other at-risk first responder/public service populations for suicidality (e.g., police, Veterans, active duty military non-deployed males; Martin et al., 2017; Stanley et al., 2015; Stanley et al., 2016). Behavioral autopsies have been utilized to elucidate the clinical picture of other at-risk populations; however, to date there is no proposed or applied model for a suicide behavior autopsy in fire personnel. Developing a standardized suicide behavior autopsy will allow for a comprehensive understanding of firefighters who die by suicide and highlight potential areas for intervention. The aim of this paper is to integrate best practices for autopsy procedures from other high-risk populations into a comprehensive theoretical model for a proposed behavioral health autopsy for firefighters. Our recommended protocol is presented along with relevant limitations, clinical implications, and recommendations for future research.

Joint analyses of human milk fatty acids, phospholipids, and choline in association with cognition and temperament traits during the first 6 months of life

Early dietary exposure via human milk nutrients offers a window of opportunity to support cognitive and temperament development. While several studies have focused on associations of few pre-selected human milk nutrients with cognition and temperament, it is highly plausible that human milk nutrients synergistically and jointly support cognitive and behavioral development in early life. We aimed to discern the combined associations of three major classes of human milk nutrients with cognition and temperament during the first 6 months of life when human milk is the primary source of an infant’s nutrition and explore whether there were persistent effects up to 18 months old. The Mullen Scales of Early Learning and Infant Behavior Questionnaires—Revised were used to assess cognition and temperament, respectively, of 54 exclusively/predominantly breastfed infants in the first 6 months of life, whose follow-ups were conducted at 6–9, 9–12, and 12–18 months old. Human milk samples were obtained from the mothers of the participants at less than 6 months of age and analyzed for fatty acids [total monounsaturated fatty acids, polyunsaturated fatty acid, total saturated fatty acid (TSFA), arachidonic acid (ARA), docosahexaenoic acid (DHA), ARA/DHA, omega-6/omega-3 polyunsaturated fatty acids ratio (n-6/n-3)], phospholipids [phosphatidylcholine, phosphatidylethanolamine (PE), phosphatidylinositol (PI), sphingomyelin], and choline [free choline, phosphocholine (PCho), glycerophosphocholine]. Feature selection was performed to select nutrients associated with cognition and temperament. The combined effects of selected nutrients were analyzed using multiple regression. A positive association between the arachidonic acid (ARA) and surgency was observed (p = 0.024). A significant effect of DHA, n-6/n-3, PE, and TSFA concentrations on receptive language (R² = 0.39, p = 0.025) and the elevated ARA, PCho, and PI with increased surgency (R² = 0.43, p = 0.003) was identified, suggesting that DHA and ARA may have distinct roles for temperament and language functions. Furthermore, the exploratory association analyses suggest that the effects of human milk nutrients on R.L. and surgency may persist beyond the first 6 months of life, particularly surgency at 12–18 months (p = 0.002). Our study highlighted that various human milk nutrients work together to support the development of cognition and temperament traits during early infancy.

The Effectiveness of Virtual Lactation Support: A Systematic Review and Meta-Analysis

BACKGROUND

The World Health Organization recommends lactation support to enhance the rates of exclusive breastfeeding. Access to in person lactation support may be limited due to scarcity of resources (e.g., healthcare professionals) and geography. Advances in technology have allowed lactation supports to be offered virtually through information and communication technologies (i.e., telephone, internet, and social media).

RESEARCH AIMS

To (1) critically review and (2) statistically analyze the effectiveness of virtual lactation support for postpartum mothers' exclusive breastfeeding for up to 6 months.

METHODS

A systematic review and meta-analysis were conducted using PRISMA guidelines. Studies were included if they were (a) randomized controlled trials, (b) with a virtual lactation support intervention during the postpartum period, (c) reported on exclusive breastfeeding outcomes. Two reviewers independently assessed the risk of bias and extracted data. The prevalence of exclusive breastfeeding in each group and the total number of participants randomized for each group were entered into random-effects meta-analyses to calculate a pooled relative risk (RR) at three different time points (1, 4, and 6 months). The sample size was 19 randomized control trials.

RESULTS

Of the 19 studies, 16 (84.2%) were included in the meta-analysis (n = 5,254). Virtual lactation support was found to be effective at increasing exclusive breastfeeding at 1 month (RR, 1.21; 95% CI [1.09, 1.35]; p < .001) and 6 months (RR, 1.87; 95% CI [1.30, 2.68]; p < .001).

CONCLUSION

In this meta-analysis of randomized controlled trials comparing virtual lactation support with other postnatal maternity care, virtual lactation support was associated with increasing exclusive breastfeeding rates at 1 month and 6 months postpartum.The study protocol was registered (CRD42021256433) with PROSPERO.

An ode to fetal, infant, and toddler neuroimaging: Chronicling early clinical to research applications with MRI, and an introduction to an academic society connecting the field

Fetal, infant, and toddler neuroimaging is commonly thought of as a development of modern times (last two decades). Yet, this field mobilized shortly after the discovery and implementation of MRI technology. Here, we provide a review of the parallel advancements in the fields of fetal, infant, and toddler neuroimaging, noting the shifts from clinical to research use, and the ongoing challenges in this fast-growing field. We chronicle the pioneering science of fetal, infant, and toddler neuroimaging, highlighting the early studies that set the stage for modern advances in imaging during this developmental period, and the large-scale multi-site efforts which ultimately led to the explosion of interest in the field today. Lastly, we consider the growing pains of the community and the need for an academic society that bridges expertise in developmental neuroscience, clinical science, as well as computational and biomedical engineering, to ensure special consideration of the vulnerable mother-offspring dyad (especially during pregnancy), data quality, and image processing tools that are created, rather than adapted, for the young brain.

Dear reviewers: Responses to common reviewer critiques about infant neuroimaging studies

The field of adult neuroimaging relies on well-established principles in research design, imaging sequences, processing pipelines, as well as safety and data collection protocols. The field of infant magnetic resonance imaging, by comparison, is a young field with tremendous scientific potential but continuously evolving standards. The present article aims to initiate a constructive dialog between researchers who grapple with the challenges and inherent limitations of a nascent field and reviewers who evaluate their work. We address 20 questions that researchers commonly receive from research ethics boards, grant, and manuscript reviewers related to infant neuroimaging data collection, safety protocols, study planning, imaging sequences, decisions related to software and hardware, and data processing and sharing, while acknowledging both the accomplishments of the field and areas of much needed future advancements. This article reflects the cumulative knowledge of experts in the FIT’NG community and can act as a resource for both researchers and reviewers alike seeking a deeper understanding of the standards and tradeoffs involved in infant neuroimaging.

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The field of infant MRI is young with evolving standards.

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We address 20 questions that researchers commonly receive reviewers.

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These come from research ethics boards, grant, and manuscript reviewers.

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This article reflects the cumulative knowledge of experts in the FIT’NG community.

Early-Life Nutrition and Cognitive Development: Imaging Approaches

Brain development in the first years of life is the most dynamic and perhaps the most important phase of brain maturation. While it is widely recognized that nutrition plays a key role in early brain development, particular nutrients will most likely differentially affect distinct aspects of brain development. The critical dosage windows and time frames for various nutrients at different stages of brain development are likely dissimilar. Therefore, efforts have been devoted to identifying potential associations between nutrients and early brain development. However, behavioral assessments are typically employed as the outcome measures, which are known to suffer from low sensitivity and the inability to provide neural substrates underlying brain functional maturation. In contrast, magnetic resonance imaging is capable of providing detailed anatomical and functional information - an ideal tool to characterize brain functional development and nutrition. Our team has developed strategies that enable imaging of typically developing children from birth to teens without sedation. Quantitative assessments of brain structural and functional development during the first years of life have been accomplished, which reveal important features of early brain development. These developed tools will most likely substantially enhance our ability to rigorously characterize the interplay between nutrients and early brain development.

Early Developmental Trajectories of Functional Connectivity Along the Visual Pathways in Rhesus Monkeys

Early social interactions shape the development of social behavior, although the critical periods or the underlying neurodevelopmental processes are not completely understood. Here, we studied the developmental changes in neural pathways underlying visual social engagement in the translational rhesus monkey model. Changes in functional connectivity (FC) along the ventral object and motion pathways and the dorsal attention/visuo-spatial pathways were studied longitudinally using resting-state functional MRI in infant rhesus monkeys, from birth through early weaning (3 months), given the socioemotional changes experienced during this period. Our results revealed that (1) maturation along the visual pathways proceeds in a caudo-rostral progression with primary visual areas (V1-V3) showing strong FC as early as 2 weeks of age, whereas higher-order visual and attentional areas (e.g., MT-AST, LIP-FEF) show weak FC; (2) functional changes were pathway-specific (e.g., robust FC increases detected in the most anterior aspect of the object pathway (TE-AMY), but FC remained weak in the other pathways (e.g., AST-AMY)); (3) FC matures similarly in both right and left hemispheres. Our findings suggest that visual pathways in infant macaques undergo selective remodeling during the first 3 months of life, likely regulated by early social interactions and supporting the transition to independence from the mother.

Intraluminal Carotid Artery Thrombus in COVID-19: Another Danger of Cytokine Storm?

Coronavirus disease 2019 (COVID-19) is associated with a severe inflammatory response. Inflammation affects atherosclerotic plaque vulnerability and promotes a thrombogenic environment. We report a series of 6 patients with COVID-19 with acute ischemic stroke due to intraluminal carotid artery thrombus presenting during an 8-day period. Six patients were included (5 men) with a mean age of 65.8 years (range, 55-78 years). COVID-19 was diagnosed by detection of Severe Acute Respiratory Syndrome coronavirus 2 in 5 patients and was presumed due to typical clinical and imaging findings in 1 patient. All patients had vascular risk factors including diabetes (83%), hyperlipidemia (100%), and smoking (17%). Four patients presented with large infarcts with initial NIHSS scores of 24-30. During their hospitalization, all patients had elevated D-dimer and C-reactive protein levels, 5 patients had elevated lactate dehydrogenase and ferritin levels, 3 had elevated interleukin-6 levels, and 2 had elevated troponin levels. Inflammation related to COVID-19 may result in rupture of vulnerable atherosclerotic plaques, resulting in thrombosis and acute ischemic stroke.

UNC-Emory Infant Atlases for Macaque Brain Image Analysis: Postnatal Brain Development through 12 Months

Computational anatomical atlases have shown to be of immense value in neuroimaging as they provide age appropriate reference spaces alongside ancillary anatomical information for automated analysis such as subcortical structural definitions, cortical parcellations or white fiber tract regions. Standard workflows in neuroimaging necessitate such atlases to be appropriately selected for the subject population of interest. This is especially of importance in early postnatal brain development, where rapid changes in brain shape and appearance render neuroimaging workflows sensitive to the appropriate atlas choice. We present here a set of novel computation atlases for structural MRI and Diffusion Tensor Imaging as crucial resource for the analysis of MRI data from non-human primate rhesus monkey (Macaca mulatta) data in early postnatal brain development. Forty socially-housed infant macaques were scanned longitudinally at ages 2 weeks, 3, 6, and 12 months in order to create cross-sectional structural and DTI atlases via unbiased atlas building at each of these ages. Probabilistic spatial prior definitions for the major tissue classes were trained on each atlas with expert manual segmentations. In this article we present the development and use of these atlases with publicly available tools, as well as the atlases themselves, which are publicly disseminated to the scientific community.

The international society for developmental psychobiology Sackler symposium: early adversity and the maturation of emotion circuits--a cross-species analysis

Early-life caregiving shapes the architecture and function of the developing brain. The fact that the infant-caregiver relationship is critically important for infant functioning across all altricial species, and that the anatomical circuits supporting emotional functioning are highly preserved across different species, suggests that the results of studies examining the role of early adversity and emotional functioning should be translatable across species. Here we present findings from four different research laboratories, using three different species, which have converged on a similar finding: adversity accelerates the developmental trajectory of amygdala-prefrontal cortex (PFC) development and modifies emotional behaviors. First, a rodent model of attachment learning associated with adversity is presented showing precocial disruption of attachment learning and emergence of heightened fear learning and emotionality. Second, a model of infant-mother separation is presented in which early adversity is shown to accelerate the developmental emergence of adult-like fear retention and extinction. Third, a model of early life adversity in Rhesus monkeys is presented in which a naturally occurring variation in maternal-care (abuse) is shown to alter the functioning of emotion circuits. Finally, a human model of maternal deprivation is presented in which children born into orphanages and then adopted abroad exhibit aberrant development of emotion circuits. The convergence of these cross-species studies on early life adversity suggests that adversity targets the amygdala and PFC and has immediate impact on infant behavior with the caregiver, and emotional reactions to the world. These results provide insight into mechanisms responsible for caregiver induced mental health trajectory alterations.

First Report of Arceuthobium aureum subsp. aureum in Mexico

The golden dwarf mistletoe (Arceuthobium aureum Hawksw. & Wiens subsp. aureum, Viscaceae) parasitizes several pines (Pinus spp., Pinaceae) in central Guatemala (1). In September 2006, we observed golden dwarf mistletoe parasitizing Pinus maximinoi H.E. Moore in southern Chiapas, Mexico; 1 km west of El Rosario along Mexico Route 211 (15°19'23″N, 92°17'45″W, elevation 1,720m). Golden dwarf mistletoe can be distinguished from the closely related Peterson's dwarf mistletoe (A. aureum Hawksw. & Wiens subsp. petersonii Hawksw. & Wiens) by its smaller shoots, occurrence below 2,200 m in elevation, and flowering period (1). The shoots of the dwarf mistletoe at the El Rosario location were less than 20 cm high and male plants were not flowering. Male plants of Peterson's dwarf mistletoe observed at the type locality and other locations in Chiapas during September were in full flower. Although only 29 trees were infected at this location, infection was severe on 11 trees, but no mortality associated with dwarf mistletoe infection was observed. Mistletoe infection did not induce the formation of witches'-brooms near El Rosario, but infection by golden dwarf mistletoe on P. maximinoi does induce witches'-brooms on older trees in Guatemala (2). The golden dwarf mistletoe population near El Rosario is approximately 150 km west of the nearest known population of this species in Guatemala (1). To our knowledge, this is the first report of golden dwarf mistletoe in Mexico. Specimens of golden dwarf mistletoe from Chiapas, Mexico were deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff (Accession No. 83122). References: (1) F. Hawksworth and D. Wiens. Dwarf Mistletoes: Biology, Systematics, and Pathology. USDA For. Serv. Agric. Handb. 709, 1996. 2) R. Mathiasen et al. Madrono 23:122, 2004.

First Report of Psittacanthus macrantherus on Pinus devoniana and Quercus castanea in Mexico

The mistletoe Psittacanthus macrantherus Eichl. (Loranthaceae) is an important parasite of pines (Pinus spp., Pinaceae) in Mexico (1). It has been reported to parasitize Pinus engelmannii Carr., P. herrerai Mart., P. lawsonii Roezl ex Gord. & Glend., P. lumholtzii Robins & Fern., P. oocarpa Schiede, and P. pseudostrobus Lindl. (1). During July 2005, we found this mistletoe parasitizing P. devoniana Lindl. and Quercus castanea Nee near Route 40 in Sinaloa, Mexico approximately 12 km west of El Palmito (23°30'N, 105°07'W, elevation 1,900 m). The mistletoe was common in P. devoniana, and some trees were severely infected (>10 plants per tree). However, no mortality associated with mistletoe infection in P. devoniana was observed. Only one infected tree of Q. castanea was observed in this area and it was not severely infected. We also observed this mistletoe on P. douglasiana Mart. along Route 40 west and east of El Palmito, but no specimens were collected because plants were very high in the crowns of the infected trees. To our knowledge, this is the first report of this mistletoe parasitizing P. devoniana, P. douglasiana, and Q. castanea (1). Specimens of Psittacanthus macrantherus from P. devoniana and Q. castenea have been deposited at the Deaver Herbarium (ASC), Northern Arizona University, Flagstaff (Accession Nos. 79534 and 79535). References: (1) B. Geils et al. Mistletoes of North American conifers. USDA For. Serv. Gen. Tech. Rep. RMRS-GTR-98, 2002.

First Report of Cladocolea cupulata on Pinus douglasiana and P. herrerai in Northern Mexico

The mistletoe Cladocolea cupulata Kuijt (Loranthaceae) has previously been reported parasitizing pines (Pinus spp., Pinaceae) in central Mexico (3). As of today, reported pine hosts have been Pinus jaliscana Pérez de la Rosa and P. lumholtzii B.L. Rob. & Fernald from the state of Jalisco (1,2). During July 2005, we found this mistletoe parasitizing P. douglasiana Martinez and P. herrerai Martinez along Route 40 in Durango approximately 8 km east of El Palmito (23°35'54″N, 105°50'45″W, elevation 2,000 m). We also found the mistletoe on P. douglasiana along Route 40 at approximately 18 km west of El Palmito (23°27'51″N, 105°49'58″W, elevation 1,780 m) in the state of Sinaloa. Additional populations of this mistletoe were observed along the roadside of Route 40 in the Sinaloa-Durango border region. Infected trees had one to five mistletoe plants on them. Comparing infected hosts with neighboring noninfected hosts, the mistletoe appeared to have no effect on the growth of the infected trees. No mortality associated with mistletoe infection was observed for either of these mistletoe-host combinations. C. cupulata can be distinguished from its closest relatives, C. grahami Kuijt and C. pringlei Kuijt, by its longer, narrower, opposite leaves, parallel venation, and the saddle-like peduncles that hold four flowers (3). The other taxa have predominantly alternate leaves with pinnate venation and lack the saddle-like peduncle. To our knowledge, this is the first report of C.cupulata parasitizing P. douglasiana and P. herrerai and the first report of this mistletoe from the states of Durango and Sinaloa (2,3). Specimens of C. cupulata and host material were collected and have been deposited at the Deaver Herbarium (ASC), Northern Arizona University, Flagstaff (Accession Nos. 79532, 79533, and 79536). References: (1) B. Chazado. Biosphera 1:3, 1990. (2) B. Geils et al. USDA For. Serv. Gen. Tech. Rep. RMRS-GTR-98, 2002. (3) J. Kuijt. J. Arnold Arbor. Harv. Univ. 56:265, 1975.

First Report of Arceuthobium hawksworthii in Honduras

The dwarf mistletoe Arceuthobium hawksworthii D. Wiens & C. G. Shaw (Viscaceae) has only been reported from the Mountain Pine Ridge area of Belize (1). We observed this dwarf mistletoe parasitizing its principal host, Caribbean pine (Pinus caribaea Morelet var. hondurensis (Senecl.) Barrett & Golf.) (1), 10 km east of Gualaco, Department Olancho, Honduras (elevation 800 m). Several trees were severely infected, and some dwarf mistletoe-associated mortality was observed at this location. The identification of A. hawksworthii was confirmed by comparing specimens collected from Honduras with specimens from Belize, which are deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff. The mistletoes Psittacanthus angustifolius Kuijt and P. pinicola Kuijt (Loranthaceae) were also observed at this location parasitizing Caribbean pine. However, infection by both of these mistletoes was not severe, and no mistletoe-associated mortality was observed. Specimens of these mistletoes from Caribbean pine have been deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras. To our knowledge, this is the first report of A. hawksworthii from Honduras and extends its range approximately 350 km to the east-southeast of the Mountain Pine Ridge in Belize. This is also the first report P. angustifolius on Caribbean pine, but P. pinicola commonly infects this host in northern Honduras and Belize (2). References: (1) F. G. Hawksworth and D. Wiens. Dwarf mistletoes: biology, pathology, and systematics. Agric. Handb. 709, 1996. (2) J. Kuijt. Ann. Mo. Bot. Gard. 74:511, 1987.

First Report of Phoradendron breedlovei in Honduras

The mistletoe Phoradendron breedlovei Kuijt (family Viscaceae) has only been reported from two locations in Chiapas, Mexico (1). We observed this mistletoe parasitizing Quercus salicifolia Nee approximately 4 km east of La Esperanza, Department Intibuca, Honduras, at an elevation of 1,160 m. Several trees were severely infected, and some mortality appeared to be associated with severe infection. J. Kuijt, University of Victoria, British Columbia, Canada, confirmed our identification of the mistletoe. Specimens of P. breedlovei from Honduras have been deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras, and at the University of Victoria. To our knowledge, this is the first report of P. breedlovei from Honduras and extends the range of this mistletoe approximately 500 km to the east-southeast of Chiapas. To our knowledge, it is also the first report of this mistletoe on Q. salicifolia. Reference: (1) J. Kuijt. Proc. K. Ned. Akad. Wet. 93:113, 1990.

disabled-1 functions cell autonomously during radial migration and cortical layering of pyramidal neurons

Genetic mosaics offer an excellent opportunity to analyze complex gene functions. Chimeras consisting of mutant and wild-type cells provide not only the avenue for lineage-specific gene rescue but can also distinguish cell-autonomous from non-cell-autonomous gene functions. Using an independent genetic marker for wild-type cells, we constructed Dab1(+/+) <--> Dab1(-/-) chimeras with the aim of discovering whether or not the function of Dab1 during neuronal migration and cortical layering is cell autonomous. Dab1(+/+) cells were capable of radial migration and columnar formation in a Dab1(-/-)environment. Most Dab1(+/+) cells segregated to the superficial part of the mutant cortex, forming a multilayered supercortex. Neuronal birth-dating studies indicate that supercortex neurons were correctly layered, although adjacent mutant cortex neurons were in reversed order. Immunocytochemistry using Emx1, a marker for pyramidal neurons, indicates that the vast majority of Dab1(+/+) neurons in the supercortex were Emx1 immunoreactive. Confirmation of the pyramidal phenotype was demonstrated by the absence of GABA immunoreactivity among Dab1(+/+) cells in the supercortex. Myelin staining using 2'3'-cyclic nucleotide 3'-phosphodiesterase showed the supercortex was supported by a secondary white matter from which thick fiber tracts appear connected to the underlying mutant white matter. The presence of Dab1(+/+) cells failed to rescue inversion of cortical layers and the abnormal infiltration of the marginal zone by Dab1(-/-) cells. Conversely, mutant cells did not impose a mutant phenotype on adjacent wild-type neurons. These results suggest that Dab1 functions cell autonomously with respect to radial migration and cortical layering of pyramidal neurons.

First Report of Psittacanthus angustifolius on Psidium guineense and Pinus tecunumanii in Honduras

The mistletoe Psittacanthus angustifolius Kuijt (Loranthaceae) is a common parasite of pines in Central America and southern Mexico (1,2). In August 2000, we observed this mistletoe parasitizing a wild guava tree, Psidium guineense Sw., ≈5 km north of Yamaranguila, Department Intibuca, Honduras, at an elevation of 1,800 m. Only one plant was found on a single tree, and wild guava is apparently a rare host for this mistletoe because we have not observed this host-parasite combination in other areas where Psidium guineense occurs. This is the first report of P. angustifolius on a plant other than Pinus spp. In November 2000, we observed this mistletoe parasitizing Pinus tecunumanii (Schw.) Eguiluz et Perry ≈4 km north of Opatoro, Department La Paz, Honduras, at an elevation of 1,700 m. Several pines were infected, but no trees had more than five mistletoe infections. To our knowledge, this is the first report of P. angustifolius on P. tecunumanii in Honduras, although it is known to occur on this host in Chiapas, Mexico. Specimens of P. angustifolius from these hosts have been deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras. References: (1) R. Mathiasen et al. Plant Dis. 84:203, 2000. (2) R. Mathiasen et al. Plant Dis. 84:808, 2000.

First Report of Arceuthobium globosum subsp. grandicaule in Honduras

Large-stemmed dwarf mistletoe (Arceuthobium globosum Hawksw. & Wiens subsp. grandicaule Hawksw. & Wiens-Viscaceae) parasitizes several Pinus spp. in central Mexico and western Guatemala (1). In November 2000 several trees of Pinus hartwegii Lindley were discovered being parasitized by this dwarf mistletoe near the summit of Cerro las Minas, Montana de Celaque (2850 m elevation) approximately 12 km southwest of Gracias, Department Lempira, Honduras. Species identification was based on the size of the plants, which were greater than 50 cm in height, and the dark brown color and size (2.1 to 4.5 cm) of the stem base (1). There was no apparent infection of nearby Pinus ayacahuite Ehrenb., which is known to be immune to the pathogen. Specimens of A. globosum subsp. grandicaule were collected and deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras and at the Deaver Herbarium, Northern Arizona University, Flagstaff. To our knowledge, this is the first report of this dwarf mistletoe in Honduras and extends its eastern distribution from west-central Guatemala by approximately 300 km. Reference: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. USDA Agric. Handb. 709.

The catastrophe-promoting activity of ectopic Op18/stathmin is required for disruption of mitotic spindles but not interphase microtubules

Oncoprotein18/stathmin (Op18) is a microtubule (MT) destabilizing protein that is inactivated during mitosis by phosphorylation at four Ser-residues. Op18 has at least two functions; the N-terminal region is required for catastrophe-promotion (i.e., transition from elongation to shortening), while the C-terminal region is required to inhibit MT-polymerization rate in vitro. We show here that a "pseudophosphorylation" derivative of Op18 (i.e., four Ser- to Glu-substitutions at phosphorylation sites) exhibits a selective loss of catastrophe-promoting activity. This is contrasted to authentic phosphorylation, which efficiently attenuates all activities except tubulin binding. In intact cells, overexpression of pseudophosphorylated Op18, which is not phosphorylated by endogenous kinases, is shown to destabilize interphase MTs but to leave spindle formation untouched. To test if the mitotic spindle is sensitive only to the catastrophe-promoting activity of Op18 and resistant to C-terminally associated activities, N- and C-terminal truncations with defined activity-profiles were employed. The cell-cycle phenotypes of nonphosphorylatable mutants (i.e., four Ser- to Ala-substitutions) of these truncation derivatives demonstrated that catastrophe promotion is required for interference with the mitotic spindle, while the C-terminally associated activities are sufficient to destabilize interphase MTs. These results demonstrate that specific Op18 derivatives with defined activity-profiles can be used as probes to distinguish interphase and mitotic MTs.

Kinase and phosphatase inhibitors cause rapid alterations in microtubule dynamic instability in living cells

To examine whether microtubule dynamic instability can be rapidly regulated during interphase, we used video-enhanced differential interference contrast (DIC) microscopy to observe individual microtubules at the periphery of living newt lung epithelial cells. Microtubules were observed before and after perfusion with either the phosphatase inhibitor okadaic acid or the kinase inhibitors staurosporine or olomoucine. Addition of these inhibitors caused rapid changes in dynamic instability. Thirty to sixty seconds after perfusion with 0.2-1 microM okadaic acid, a 1.5-fold increase in elongation velocity and small increases in catastrophe and rescue frequencies were observed. In contrast, treatment with 40-200 nM staurosporine decreased microtubule elongation and shortening velocities approximately 2-fold, and catastrophes were slightly more frequent. Olomoucine, at 100 microM, had similar effects. Transition dynamics were further examined by probabilistic analysis, which showed that microtubules become more likely to undergo catastrophe as they elongated and more likely to undergo rescue as they shortened, an effect previously called microtubule "memory." This memory effect for catastrophes was observed in untreated and okadaic acid-treated cells but was abolished by staurosporine or olomoucine. In contrast, the memory effect for rescue was unaffected by these treatments, suggesting that catastrophe and rescue proceed via distinct, multistep mechanisms. Overall, these results demonstrate that microtubule assembly regulators can be altered rapidly by inhibition of either kinases or phosphatases and suggest that, in the absence of inhibitors, these regulators exist in a dynamic equilibrium between phosphorylated and dephosphorylated states.

Decreasing oncoprotein 18/stathmin levels reduces microtubule catastrophes and increases microtubule polymer in vivo

Oncoprotein 18/stathmin (Op18) has been identified recently as a protein which destabilizes microtubules. To characterize the function of Op18 in living cells, we used microinjection of anti-Op18 antibodies or antisense oligonucleotides to block either Op18 activity or expression in interphase newt lung cells. Anti-tubulin staining of cells microinjected with anti-Op18 and fixed 1–2 hours after injection showed an increase in total microtubule polymer. In contrast, microinjection of either non-immune IgG or anti-Op18 preincubated with bacterially-expressed Op18 had little effect on microtubule polymer level. Cells treated with Op18 antisense oligonucleotides for 4 days had (greater than or equal to)50% reduced levels of Op18 with no change in the soluble tubulin level. Measurement of MT polymer level in untreated, antisense or nonsense oligonucleotide treated cells demonstrated that reduced Op18 levels resulted in a 2.5-fold increase in microtubule polymer. Next, the assembly dynamics of individual microtubules at the peripheral regions of living cells were examined using video-enhanced contrast DIC microscopy. Microinjection of antibodies against oncoprotein 18 resulted in a 2.2-fold reduction in catastrophe frequency and a slight reduction in plus end elongation velocity compared to uninjected cells or cells microinjected with non-immune IgG. Preincubation of anti-Op18 antibody with recombinant Op18 greatly diminished the effects of the antibody. Similarly, treatment of cells with antisense oligonucleotides reduced catastrophes 2.5- to 3-fold compared to nonsense oligonucleotide treated or untreated cells. The other parameters of dynamic instability were unchanged after reducing Op18 with antisense oligonucleotides. These studies are consistent with Op18 functioning to regulate microtubule catastrophes during interphase in vivo.

Dissociation of the tubulin-sequestering and microtubule catastrophe-promoting activities of oncoprotein 18/stathmin

Oncoprotein 18/stathmin (Op18) has been identified recently as a protein that destabilizes microtubules, but the mechanism of destabilization is currently controversial. Based on in vitro microtubule assembly assays, evidence has been presented supporting conflicting destabilization models of either tubulin sequestration or promotion of microtubule catastrophes. We found that Op18 can destabilize microtubules by both of these mechanisms and that these activities can be dissociated by changing pH. At pH 6.8, Op18 slowed microtubule elongation and increased catastrophes at both plus and minus ends, consistent with a tubulin-sequestering activity. In contrast, at pH 7.5, Op18 promoted microtubule catastrophes, particularly at plus ends, with little effect on elongation rates at either microtubule end. Dissociation of tubulin-sequestering and catastrophe-promoting activities of Op18 was further demonstrated by analysis of truncated Op18 derivatives. Lack of a C-terminal region of Op18 (aa 100-147) resulted in a truncated protein that lost sequestering activity at pH 6.8 but retained catastrophe-promoting activity. In contrast, lack of an N-terminal region of Op18 (aa 5-25) resulted in a truncated protein that still sequestered tubulin at pH 6.8 but was unable to promote catastrophes at pH 7.5. At pH 6. 8, both the full length and the N-terminal-truncated Op18 bound tubulin, whereas truncation at the C-terminus resulted in a pronounced decrease in tubulin binding. Based on these results, and a previous study documenting a pH-dependent change in binding affinity between Op18 and tubulin, it is likely that tubulin sequestering observed at lower pH resulted from the relatively tight interaction between Op18 and tubulin and that this tight binding requires the C-terminus of Op18; however, under conditions in which Op18 binds weakly to tubulin (pH 7.5), Op18 stimulated catastrophes without altering tubulin subunit association or dissociation rates, and Op18 did not depolymerize microtubules capped with guanylyl (alpha, beta)-methylene diphosphonate-tubulin subunits. We hypothesize that weak binding between Op18 and tubulin results in free Op18, which is available to interact with microtubule ends and thereby promote catastrophes by a mechanism that likely involves GTP hydrolysis.

Purification of a WD repeat protein, EMAP, that promotes microtubule dynamics through an inhibition of rescue

The major microtubule-associated protein in echinoderms is a 77-kDa, WD repeat protein, called EMAP. EMAP-related proteins have been identified in sea urchins, starfish, sanddollars, and humans. We describe the purification of sea urchin EMAP and demonstrate that EMAP binding to microtubules is saturable at a molar ratio of 1 mol of EMAP to 3 mol of tubulin dimer. Unlike MAP-2, MAP-4, or tau proteins, EMAP binding to microtubules is not lost by cleavage of tubulin with subtilisin. In addition to binding to the microtubule polymer, EMAP binds to tubulin dimers in a 1:1 molar ratio. The abundance of EMAP in the egg suggests that it could function to regulate microtubule assembly. To test this hypothesis, we examined the effects of EMAP on the dynamic instability of microtubules nucleated from axoneme fragments as monitored by video-enhanced differential interference contrast microscopy. Addition of 2.2 microM EMAP to 21 microM tubulin results in a slight increase in the elongation and shortening velocities at the microtubule plus ends but not at the minus ends. Significantly, EMAP inhibits the frequency of rescue 8-fold without producing a change in the frequency of catastrophe. These results indicate that EMAP, unlike brain microtubule-associated proteins, promotes microtubule dynamics.

Nanomolar concentrations of nocodazole alter microtubule dynamic instability in vivo and in vitro

Previous studies demonstrated that nanomolar concentrations of nocodazole can block cells in mitosis without net microtubule disassembly and resulted in the hypothesis that this block was due to a nocodazole-induced stabilization of microtubules. We tested this hypothesis by examining the effects of nanomolar concentrations of nocodazole on microtubule dynamic instability in interphase cells and in vitro with purified brain tubulin. Newt lung epithelial cell microtubules were visualized by video-enhanced differential interference contrast microscopy and cells were perfused with solutions of nocodazole ranging in concentration from 4 to 400 nM. Microtubules showed a loss of the two-state behavior typical of dynamic instability as evidenced by the addition of a third state where they exhibited little net change in length (a paused state). Nocodazole perfusion also resulted in slower elongation and shortening velocities, increased catastrophe, and an overall decrease in microtubule turnover. Experiments performed on BSC-1 cells that were microinjected with rhodamine-labeled tubulin, incubated in nocodazole for 1 h, and visualized by using low-light-level fluorescence microscopy showed similar results except that nocodazole-treated BSC-1 cells showed a decrease in catastrophe. To gain insight into possible mechanisms responsible for changes in dynamic instability, we examined the effects of 4 nM to 12 microM nocodazole on the assembly of purified tubulin from axoneme seeds. At both microtubule plus and minus ends, perfusion with nocodazole resulted in a dose-dependent decrease in elongation and shortening velocities, increase in pause duration and catastrophe frequency, and decrease in rescue frequency. These effects, which result in an overall decrease in microtubule turnover after nocodazole treatment, suggest that the mitotic block observed is due to a reduction in microtubule dynamic turnover. In addition, the in vitro results are similar to the effects of increasing concentrations of GDP-tubulin (TuD) subunits on microtubule assembly. Given that nocodazole increases tubulin GTPase activity, we propose that nocodazole acts by generating TuD subunits that then alter dynamic instability.

Phylogenetic analysis of the mitochondrial genomes from Leber hereditary optic neuropathy pedigrees

The nucleotide sequences of the mitochondrial genomes from patients with Leber hereditary optic neuropathy (LHON) were used for phylogenetic analysis to study the origin and population history of pathogenic mitochondrial mutations. Sequences of both the coding region (8300 bp) and the more rapidly evolving noncoding control region (1300 bp) were analyzed. Patients with the primary LHON mutations at nucleotides 3460, 11,778, and 14,484 were included in this study, as were LHON patients and non-LHON controls that lacked these primary mutations; some of the subjects also carried secondary LHON mutations. The phylogenetic analyses demonstrate that primary LHON mutations arose and were fixed multiple times within the population, even for the small set of LHON patients that was analyzed in these initial studies. In contrast, the secondary LHON mutations at nucleotides 4216, 4917, and 13,708 arose once: the mitochondrial genomes that carried these secondary mutations formed a well-supported phylogenetic cluster that apparently arose 60,000 to 100,000 years ago. Previous studies found secondary LHON mutations at a higher frequency among LHON patients than among control subjects. However, this finding does not prove a pathogenetic role of these mutations in LHON. Instead, the increased frequency is more likely to reflect the population genetic history of secondary mutations relative to that of primary LHON mutations.

Modulation of hepatic mRNA translation activity and specific expression of arylsulfotransferase IV during acetylaminofluorene-induced rat hepatocarcinogenesis

Enzymatic sulfation of N-hydroxylated arylamines by mammalian hepatic cytosol sulfotransferases (AST; EC 2.8.2.1) is an important metabolic step which generates ultimate carcinogens. The metabolic activity of AST IV, the putative isozymic form of AST primarily responsible for catalyzing N-hydroxy-2-acetylaminofluorene sulfation, is modulated during 2-acetylaminofluorene (AAF)-induced rat hepatocarcinogenesis. To characterize the molecular mechanisms regulating the differential expression of AST IV, we have assessed polyadenylated mRNA derived from the livers of Sprague-Dawley rats undergoing different stages of AAF hepatocarcinogenesis for general in vitro translation capacity and specific expression of AST IV and albumin. Following 1 and 3 cycles of a cyclical feeding regimen (3 weeks 0.05% AAF, then 1 week basal diet), the mRNA capacity for translation was lowered and the expression of AST IV and albumin was down-regulated about 2-fold each but recovered to normal levels when treated rats were subsequently placed on basal diet for 3 continuous weeks. Cytosolic albumin levels were determined by Western blot analysis to be lowered about 1.5-2-fold. In contrast, however, mRNA from rats on basal diets for 3 weeks subsequent to cycle 5 of the feeding regimen recovered only about 50% of the capacity for AST IV expression, although overall translation capacity and albumin expression returned to normal levels. This pattern of reversible expression, followed by irreversible expression of AST IV at early and late stages of AAF hepatocarcinogenesis, respectively, provides the first evidence correlating the modulation of hepatic mRNA capacity for AST IV expression with differential cytosolic AST IV activity in the AAF hepatocarcinogenesis model. The results further suggest that during early stages in hepatocarcinogenesis modulation of mRNA protein synthesis functions may be a critical factor in AAF-mediated lowering of AST IV expression, while other persistent genetic lesions are likely playing a more significant role at the late stages of the carcinogenic process leading to neoplastic transformation of initiated hepatocytes.

The molecular basis of inhibitor resistance in a mammalian mitochondrial cytochrome b mutant

The mitochondrial gene for the cytochrome b of Complex III has been cloned from a mouse L-cell mutant with increased resistance to 2-n-heptyl-4-hydroxyquinoline-N-oxide and other inhibitors which block reactions at the b562 heme group. Nucleotide sequencing revealed that this gene contained a G:A transition on the coding strand at position 14,830. At the amino acid level, this mutation results in the substitution of an aspartic acid residue for a conserved glycine at position 231 of cytochrome b. Based upon current models for the secondary structure of cytochrome b, the altered amino acid lies in close proximity to one of the invariant histidine residues involved in binding the heme groups. Combining this result with the previous biochemical studies of this mutant, we hypothesize that the insertion of this highly charged side chain alters the conformation around the b562 heme group such that 2-n-heptyl-4-hydroxyquinoline-N-oxide and the other inhibitors of this group have reduced access to the inhibitor binding domain.

A quantitative, non-isotopic bioassay for interleukin 2

A quantitative bioassay for IL2 is described in which an electronic particle counter is used to measure IL2-mediated proliferation of an IL2-dependent cell line. The assay requires no radioisotopes, is comparable to tritiated thymidine incorporation and can be completely performed in about 28 hours. It can also be used to measure inhibition of IL2-mediated proliferation.

Prolactin changes after seizures classified by EEG monitoring

We examined the postictal hyperprolactinemia after seizures classified by EEG and video telemetry. Prolactin did rise after complex partial seizures that involved motor behaviors and was not further increased by secondary generalization. Nontemporal partial seizures or pseudoseizures did not demonstrate this increase. There was no difference in prolactin elevation after generalized tonic-clonic seizures, whether secondarily generalized or generalized from onset. A discriminant function accurately classified 94% of patients with pseudoseizures and 66% of patients with true cerebral seizures for an overall classification accuracy of 72%.