Connecting the Pipes: Agricultural Tile Drains and Elevated Imidacloprid Brain Concentrations in Juvenile Northern Leopard Frogs (Rana pipiens).

Neonicotinoids are neurotoxic insecticides and are often released into nearby wetlands via subsurface tile drains and can negatively impact nontarget organisms, such as amphibians. Previous studies have indicated that imidacloprid, a commonly used neonicotinoid, can cross the amphibian blood-brain barrier under laboratory conditions; however, little is known about the impact of low concentrations in a field-based setting. Here, we report aqueous pesticide concentrations at wetland production areas that were either connected or not connected to agricultural tile drains, quantified imidacloprid and its break down products in juvenile amphibian brains and livers, and investigated the relationship between imidacloprid brain concentration and brain size. Imidacloprid concentrations in brain and water samples were nearly 2.5 and 5 times higher at tile wetlands (brain = 4.12 ± 1.92 pg/mg protein; water = 0.032 ± 0.045 µg/L) compared to reference wetlands, respectively. Tile wetland amphibians also had shorter cerebellums (0.013 ± 0.001 mm), depicting a negative relationship between imidacloprid brain concentration and cerebellum length. The metabolite, desnitro-imidacloprid, had liver concentrations that were 2 times higher at tile wetlands (2 ± 0.3 µg/g). Our results demonstrate that imidacloprid can cross the amphibian blood-brain barrier under ecological conditions and may alter brain dimensions and provide insight into the metabolism of imidacloprid in amphibians.

Predictors of testosterone in zoo-managed male African elephants (Loxodonta Africana).

Reproductive complications for both male and female zoo-managed African elephants (Loxodonta africana) contribute to the rapidly declining population. In zoo-managed bull elephants, few studies have explored the potential physiological, physical, social, and environmental factors that influence bull fertility, particularly, androgen production. Testosterone is the essential steroid hormone for male sexual maturation and inadequate concentrations can be detrimental for spermatogenesis. Testosterone, fecal glucocorticoid metabolites, leptin, glucose, insulin, and triglycerides were analyzed from weekly fecal and blood serum samples taken over 6 months from six zoo-managed African elephant bulls (10-19 years of age). Testosterone levels were compared to endocrine factors, weekly social and environmental variables, daily musth signs, and body condition scores (BCS). The glucose-to-insulin ratio (G:I) was the only physiological biomarker found to be positively associated with testosterone. Predictive physical variables included Musth Score (+) and Moderate Exercise (+). Bulls with BCS signifying overweight (BCS 4) had lower testosterone (36.6 ± 1.6 ng/g fecal extraction [FE]) than bulls with healthy BCS 3; 51.2 ± 4.9 ng/g FE). Numerous social variables influenced testosterone concentrations, including Total Contact Day (+), Female Interaction Day (+), Indirect Contact Day (+), Indirect Contact Night (+) and Total No Contact (-). Both percentage of Time Outdoor and Time Mixed positively influenced testosterone, whereas testosterone decreased for percentage of Time Indoors. Each additional daily browse opportunity increased testosterone by approximately 7 ng/g FE. In managed care, the emphasis should be placed on optimizing these predictors of testosterone production to promote bull reproductive health.

Loss of TDP-43 in male germ cells causes meiotic failure and impairs fertility in mice.

Meiotic arrest is a common cause of human male infertility, but the causes of this arrest are poorly understood. Transactive response DNA-binding protein of 43 kDa (TDP-43) is highly expressed in spermatocytes in the preleptotene and pachytene stages of meiosis. TDP-43 is linked to several human neurodegenerative disorders wherein its nuclear clearance accompanied by cytoplasmic aggregates underlies neurodegeneration. Exploring the functional requirement for TDP-43 for spermatogenesis for the first time, we show here that conditional KO (cKO) of the Tardbp gene (encoding TDP-43) in male germ cells of mice leads to reduced testis size, depletion of germ cells, vacuole formation within the seminiferous epithelium, and reduced sperm production. Fertility trials also indicated severe subfertility. Spermatocytes of cKO mice showed failure to complete prophase I of meiosis with arrest at the midpachytene stage. Staining of synaptonemal complex protein 3 and γH2AX, markers of the meiotic synaptonemal complex and DNA damage, respectively, and super illumination microscopy revealed nonhomologous pairing and synapsis defects. Quantitative RT-PCR showed reduction in the expression of genes critical for prophase I of meiosis, including Spo11 (initiator of meiotic double-stranded breaks), Rec8 (meiotic recombination protein), and Rad21L (RAD21-like, cohesin complex component), as well as those involved in the retinoic acid pathway critical for entry into meiosis. RNA-Seq showed 1036 upregulated and 1638 downregulated genes (false discovery rate <0.05) in the Tardbp cKO testis, impacting meiosis pathways. Our work reveals a crucial role for TDP-43 in male meiosis and suggests that some forms of meiotic arrest seen in infertile men may result from the loss of function of TDP-43.

Electrophysiological responses to digit stimulation in a tactile oddball paradigm.

Sensory memory traces are assessed via oddball paradigms in which deviant (infrequent) stimuli are interspersed into a string of standard (frequent) stimuli. Once a memory trace for the standard is established, the deviant spurs a change detection response measured via the resulting event related potential (ERP). Response magnitude is sensitive to the differences in stimuli properties or categories and influenced by individual experience. The goal of the present study was to use ERPs to test the relation between individual digits in the somatosensory cortex and the extent to which digit representations are influenced by individual differences in experience such as independent mobility and playing video games. The present study of 60 undergraduates utilized a passive tactile oddball paradigm, stimulating the thumb, middle, and little fingers. The oddball paradigm was fully matched with each digit serving as the standard and deviant. A temporal principal component analysis (tPCA) identified factors that matched three a priori ERP components: N80, somatosensory mismatch negativity (sMMN), and P300. Analyses confirmed the anticipated differences between standards and deviants and provided some support for prior ERP work suggesting the thumb is in a different functional category than the other digits. Independent control of individual digits (such as the little finger) was positively related to only one aspect of the ERP (P3a) while video game experience was not associated with ERP differences. Cumulatively, these results provide a more nuanced examination of tactile oddball paradigms and how ERP methods can shed light on the relations between different digits.

Responses of Persons Living With Dementia to Caregiver Validating Communication: A Secondary Analysis.

Background and Purpose: Good communication between persons living with dementia and their caregivers is one important consideration when fostering a positive relationship and improving the effectiveness of care. Care can be a challenge if the person living with dementia does not feel understood or fails to cooperate with care. The individual may feel disrespected and may resist assistance. Validation therapy is a person-centered method for communicating with persons living with dementia that involves validating the experiences, feelings, and reality of an individual to encourage cooperation or provide for safety. The purpose of this study was to identify frequencies of four behavioral responses (cooperation, apathy, resistiveness, and distress) from persons living with dementia when validation communication strategies were used during care activities. Methods: This was a secondary analysis of homecare videos (n = 41) of family caregivers interacting with a person living with dementia during daily care. Behavioral coding was used to examine the relationships between validating communication and the response of a person living with dementia. Caregiver use of specific validation techniques in their communication (affirmation, acknowledging emotions, and verbalizing understanding) was coded along with subsequent responses of the person living with dementia (resistiveness, distress, apathy, or cooperation). Results: Affirmations produced an 11% probability of a cooperative response by the person living with dementia. Caregiver verbalization of understanding resulted in a 6% probability of cooperation, and silence was associated with an 8% probability of cooperation. Nonvalidating communication behaviors were associated with negative reactions. Implications for Practice: Effective person-centered communication between caregivers and persons living with dementia improved cooperation with care and decreased distress. Affirmations and verbalizing understanding were two types of validating communication more likely to elicit a cooperative response and can improve care quality, decrease caregiver burnout, and mitigate challenging behavioral responses in persons living with dementia.

Links between television exposure and toddler dysregulation: Does culture matter?

Television exposure in early childhood has increased, with concerns raised regarding adverse effects on social-emotional development, and emerging self-regulation in particular. The present study addressed television exposure (i.e., amount of time watching TV) and its associations with toddler behavioral/emotional dysregulation, examining potential differences across 14 cultures. The sample consisted of an average of 60 toddlers from each of the 14 countries from the Joint Effort Toddler Temperament Consortium (JETTC; Gartstein & Putnam, 2018). Analyses were conducted relying on the multi-level modeling framework (MLM), accounting for between- and within-culture variability, and examining the extent to which TV exposure contributions were universal vs. variable across sites. Effects of time watching TV were evaluated in relation to temperament reactivity and regulation, as well as measures of emotional reactivity, attention difficulties, and aggression. Results indicated that more time spent watching TV was associated with higher ratings on Negative Emotionality, emotional reactivity, aggression, and attention problems, as well as lower levels of soothability. However, links between TV exposure and both attention problems and soothability varied significantly between cultures. Taken together, results demonstrate that increased time spent watching television was generally associated with dysregulation, although effects were not consistently uniform, but rather varied as a function of culturally-dependent contextual factors.