The Functional Movement Screen and Self-reported Injury in Senior Military College Cadets.

INTRODUCTION: Secular trend of increasing musculoskeletal injuries (MSKIs) across all branches of the U.S. Military is a critical limiting factor in the effective and efficient process of preparing military personnel for combat. The need to evaluate functional capacity beyond current physical fitness test (PFT) standards is the key in understanding an individual's risk of noncombat-related injury. The purpose of this study is to evaluate the relationship between Functional Movement ScreenTM (FMS) scores, incidence of musculoskeletal injuries, and standardized PFT scores among freshman Cadets during their first 10 weeks of enrollment at a senior military college. MATERIALS AND METHODS: Eighty-two participants (72 male and 10 female participants; mage: 18.2 years) completed the FMS, an institution-specific PFT (2-min maximum pushups, 2-min maximum abdominal crunches, and 1.5 mile timed run), and an Incidence of Injury and Incidence of Pain Questionnaire. Independent t-tests, Spearman's rank correlation coefficients logistic regression analysis, and Receiver Operator Curves were performed to evaluate relationships between the study variables. RESULTS: FMS composite and PFT sex-normed total scores were higher in females (16.4, 236.1) than in males (15.0, 204.9). Ninety percent of all females reported injury or pain during the 10-week survey period compared to 48% of males. CONCLUSIONS: No significant difference between FMS scores and injury and pain was found within both sex groups. Therefore, use of the composite FMS score as an indicator for risk of injury or to predetermine PFT performance is not recommended for this study's population. The rate of incidence of injury or pain in Cadets during a 10-week enrolment period is high. Females outperformed males in the FMS and PFT and reported higher rates of injury and pain. The utility of the FMS may be limited when substantially scaled for implementation across entire military populations. Future research should evaluate performance associations of the FMS with Army Combat Fitness Test components in a population of equally distributed sex and race.

Holistic Functioning from a Developmental Perspective: A New Synthesis with a Focus on a Multi-tiered System Support Structure.

While research in specific academic disciplines has individually advanced knowledge and practice for promoting multiple aspects of health and well-being in children and adolescents, still missing is an understanding of the interconnectedness of many critical aspects of development and how to intentionally weave these factors to advance a more holistic approach. The need for a more holistic and inclusive approach to child and adolescent development is increasingly evident to promote long-term health and well-being as the overall percentage of children, adolescents, and adults who suffer from mental health disorders is increasing. To address this issue, our authorship team consists of researchers in the areas of developmental psychology, neuroscience, motor development, exercise science, and mental health. The collective ideas outlined in this paper are aligned to address the need to remove disciplinary-specific boundaries and elucidate synergistic linkages across multiple research domains that support holistic development and lifespan health and wellness. We propose a conceptual framework that comprehensively addresses the integration of physical, cognitive, psychological, social, and emotional domains of child and adolescent development. In addition, we also provide a holistic preventative approach that is aligned with a contemporary intervention structure (i.e., Multi-tiered Systems of Support) to promote, from a developmental perspective, positive trajectories of health and well-being across childhood and adolescence.

Potential relevance of a motor skill "proficiency barrier" on health-related fitness in youth.

This study investigated the potential impact of a motor skill proficiency barrier on measures of cardiorespiratory (CRF) and musculoskeletal (MSF) fitness in youth. A sample of 241 youth (114 girls) aged 10 - 18 years, completed the Motor Competence Assessment battery with composite scores indexed according to age- and gender-adjusted percentile scores. Motor competence (MC) levels were categorized as low (≤ 25%tile - proficiency barrier), moderate (≥ 26%tile to < 75%tile), and high (≥ 75%tile). CRF levels (Health Risk, Needs Improvement, and Healthy) were assessed using the Fitnessgram® 20 m PACER test. Low (≤ 20%tile), moderate (≥ 21%tile to ≤ 80%tile), and high (≥ 80%tile) MSF levels were assessed using grip strength normative data. Two 3 × 3 chi-square tests were conducted to determine the probability of MC level predicting CRF and MSF levels. Results demonstrated statistically significant models for performance on both the PACER (χ2[4, N = 241] = 22.65, p < .001) and grip strength (χ2[4, N = 241] = 23.95, p < .001). Strong evidence of a proficiency barrier impacting CRF was noted, as no low skilled youth met the "Healthy" fitness zone standards for PACER performance. Evidence supporting a barrier with grip strength was not as strong, as 20.8% of youth exhibiting low MC displayed high grip strength. However, all individuals with high levels of MC demonstrated at least moderate grip strength. Results emphasize the importance of developing MC during childhood as it may provide a protective effect against unhealthy CRF and MSF across youth.HighlightsThese data support the notion of Seefeldt's (1980) proficiency barrier as it relates to CRF, as no youth demonstrating low MC met the healthy fitness zone criteria for PACER performance. The development of MC may both directly and indirectly provide a protective effect against unhealthy CRF levels across childhood and adolescence.Evidence supporting a proficiency barrier with MSF as measured by grip strength was not as strong; however, all individuals with high levels of MC demonstrated at least moderate grip strength. Thus, the development of MC may be a protective factor to mitigate low levels of MSF via enhanced neuromuscular function.Promoting the development of MC in a variety of developmentally appropriate activities and settings (e.g. MC skills practice, structured and unstructured play, and performance contexts) is important to promote positive trajectories of CRF and MSF across childhood and adolescence.

Reinvest to Assess: Advancing Approaches to Motor Competence Measurement Across the Lifespan.

Measurement of motor competence is a vital process to advancing knowledge in the field of motor development. As motor competence is being more widely linked to research in other academic domains (e.g., public health, neuroscience, behavioral health), it is imperative that measurement methodology and protocols are reproducible with high degrees of validity and reliability. When addressing the plethora of available assessments, mostly developed for youth populations, there are potential questions and concerns that need to be addressed and/or clarified. One of the most prominent issues is the lack of a lifespan measure of motor competence, which is at odds with the premise of the field of motor development-studying changes in motor behavior across the lifespan. We address six areas of concern in lifespan assessment which include: (1) lack of assessment feasibility for conducting research with large samples, (2) lack of accountability for cultural significance of skills assessed, (3) limited sensitivity and discriminatory capabilities of assessments, (4) developmental and ecological validity limitations, (5) a problematic definition of 'success' in skill performance, and (6) task complexity and adaptability limitations. It is important to critically analyze current assessment methodologies as it will help us to envision the development and application of potential new assessments through a more comprehensive lens. Ultimately, we propose that reinvesting in how we think about assessment will be highly beneficial for integrating motor development from a holistic perspective, impact scientific advancements in other developmental domains, and increase global and lifespan surveillance of motor competence.

The Relationship Between Functional Motor Competence and Performance on the Army Combat Fitness Test in Army Reserve Officer Training Corps Cadets.

INTRODUCTION: The development of functional motor competence (FMC; i.e., neuromuscular coordination and control required to meet a wide range of movement goals) is critical to long-term development of health- and performance-related physical capacities (e.g., muscular strength and power, muscular endurance, and aerobic endurance). Secular decline in FMC among U.S. children and adolescents presents current and future challenges for recruiting prospective military personnel to successfully perform the physical demands of military duty. The purpose of the current study was to examine the relationship between FMC and physical military readiness (PMR) in a group of Cadets enrolled in an Army Reserve Officer Training Corps program. MATERIALS AND METHODS: Ninety Army Reserve Officer Training Corps Cadets from a southeastern university and a military college in the southeast (females = 22; Mage = 19.5 ± 2.5) volunteered for participation in the study. Cadets performed a battery of eight FMC assessments consisting of locomotor, object projection, and functional coordination tasks. To assess PMR, Cadets performed the Army Combat Fitness Test (ACFT).Values from all FMC assessments were standardized based on the sample and summed to create a composite FMC score. ACFT scores were assigned to Cadets based upon ACFT scoring standards. We used Pearson correlations to assess the relationships between individual FMC assessment raw scores, FMC composite scores, and total ACFT points. We also evaluated the potential impact of FMC on ACFT in the entire sample and within each gender subgroup using hierarchical linear regression. Finally, we implemented a 3 × 2 chi-squared analysis to evaluate the predictive utility of FMC level on pass/fail results on the ACFT by categorizing Cadets' composite FMC score into high (≥75th percentile) moderate (≥25th percentile and <75th percentile), and low (<25th percentile) based on the percentile ranks within the sample. ACFT pass/fail results were determined using ACFT standards, requiring a minimum of 60 points on each the ACFT subtests. RESULTS: FMC composite scores correlated strongly with total ACFT performance (r = 0.762) with individual FMC tests demonstrating weak-to-strong relationships ACFT performance (r = 0.200-0.769). FMC uniquely accounted for 15% (95% CI: -0.07 to 0.36) of the variance in ACFT scores in females (R2 = 0.516, F2,19 = 10.11, P < 0.001) and 26% (95% CI: 0.09-0.43) in males (R2 = 0.385, F2,65 = 20.37, P < 0.001), respectively, above and beyond the impact of age. The 3 × 2 chi-squared analysis demonstrated 74% of those with low, 28% with moderate, and 17% with high FMC failed the ACFT (χ2 [1, N = 90] = 27.717, V = 0.555, P < 0.001). CONCLUSION: FMC composite scores are strongly correlated with ACFT scores, and low levels of FMC were a strong predictor of ACFT failure. These data support the hypothesis that the development of sufficient FMC in childhood and adolescence may be a critical antecedent for PMR. Efforts to improve FMC in children and adolescents may increase PMR of future military recruits.

Utilization of outer-midplane collector probes with isotopically enriched tungsten tracer particles for impurity transport studies in the scrape-off layer of DIII-D (invited).

Triplet sets of replaceable graphite rod collector probes (CPs), each with collection surfaces on opposing faces and oriented normal to the magnetic field, were inserted at the outboard mid-plane of DIII-D to study divertor tungsten (W) transport in the Scrape-Off Layer (SOL). Each CP collects particles along field lines with different parallel sampling lengths (determined by the rod diameters and SOL transport) giving radial profiles from the main wall inward to R-R sep ∼ 6 cm. The CPs were deployed in a first-of-a-kind experiment using two toroidal rings of distinguishable isotopically enriched, W-coated divertor tiles installed at 2 poloidal locations in the divertor. Post-mortem Rutherford backscatter spectrometry of the surface of the CPs provided areal density profiles of elemental W coverage. Higher W content was measured on the probe side facing along the field lines toward the inner target indicating higher concentration of W in the plasma upstream of the CP, even though the W-coated rings were in the outer target region of the divertor. Inductively coupled plasma mass spectroscopy validates the isotopic tracer technique through analysis of CPs exposed during L-mode discharges with the outer strike point on the isotopically enriched W coated-tile ring. The contribution from each divertor ring of W to the deposition profiles found on the mid-plane collector probes was able to be de-convoluted using a stable isotope mixing model. The results provided quantitative information on the W source and transport from specific poloidal locations within the lower divertor region.

Enhancing human aspects of care with young people with muscular dystrophy: Results from a participatory qualitative study with clinicians.

BACKGROUND: Most research into clinical care of Duchenne or Becker dystrophinopathies (MD) has focused on slowing progressive muscular weakness and extending lifespan. Scarce attention has been paid to the "human" aspects of care such as psychosocial health, living a fulfilling life, or dealing with disability stigma. This study partnered with clinicians to identify and address local and systemic barriers to these human aspects of care. METHODS: We employed a participatory qualitative design at a multidisciplinary MD clinic using 2 methods: (a) ethnographic observations over a 6-month period of clinic visits of children with MD and families, involving 12 clinicians, and (b) 3 "dialogues" (2-way discussions) with these clinicians to collaboratively analyze practices and co-produce recommendations for change. RESULTS: Our methods produced rich data that, when coanalyzed with clinicians and in consultation with a family advisor, provided deep insights into the practices and underlying assumptions of a neuromuscular clinic. Staff recognized the importance of the human aspects of care but, in reviewing the observational data, identified that it was given insufficient attention in (a) routine clinical processes, (b) clinician-family patterns of interaction, and (c) staffing allocations. CONCLUSION: Although the human aspects of care were important to clinicians in the MD clinic, the routines and nature of the clinic meant these were frequently sidelined for biomedical objectives. We present collaboratively produced practical recommendations toward addressing this disjunction between ideals and practice including developing flexibility to tailor appointment frequency, composition, and length; providing time and physical space for psychosocial aspects of care; and clinician skill building to support child/family expression of "negative" emotions; and discussion of sociopolitical aspects of MD such as living with disability stigma. The study offers a set of considerations that, taking into account individual differences, offer insights for similar clinics elsewhere.

Phase II study of gemcitabine, oxaliplatin in combination with panitumumab in KRAS wild-type unresectable or metastatic biliary tract and gallbladder cancer.

BACKGROUND: Current data suggest that platinum-based combination therapy is the standard first-line treatment for biliary tract cancer. EGFR inhibition has proven beneficial across a number of gastrointestinal malignancies; and has shown specific advantages among KRAS wild-type genetic subtypes of colon cancer. We report the combination of panitumumab with gemcitabine (GEM) and oxaliplatin (OX) as first-line therapy for KRAS wild-type biliary tract cancer. METHODS: Patients with histologically confirmed, previously untreated, unresectable or metastatic KRAS wild-type biliary tract or gallbladder adenocarcinoma with ECOG performance status 0-2 were treated with panitumumab 6 mg kg(-1), GEM 1000 mg m(-2) (10 mg m(-2) min(-1)) and OX 85 mg m(-2) on days 1 and 15 of each 28-day cycle. The primary objective was to determine the objective response rate by RECIST criteria v.1.1. Secondary objectives were to evaluate toxicity, progression-free survival (PFS), and overall survival. RESULTS: Thirty-one patients received at least one cycle of treatment across three institutions, 28 had measurable disease. Response rate was 45% and disease control rate was 90%. Median PFS was 10.6 months (95% CI 5-24 months) and median overall survival 20.3 months (95% CI 9-25 months). The most common grade 3/4 adverse events were anaemia 26%, leukopenia 23%, fatigue 23%, neuropathy 16% and rash 10%. CONCLUSIONS: The combination of gemcitabine, oxaliplatin and panitumumab in KRAS wild type metastatic biliary tract cancer showed encouraging efficacy, additional efforts of genetic stratification and targeted therapy is warranted in biliary tract cancer.

A multi-institutional, phase II open-label study of ganitumab (AMG 479) in advanced carcinoid and pancreatic neuroendocrine tumors.

The IGF pathway has been implicated in the regulation of neuroendocrine tumor (NET) growth, and preliminary studies suggested that ganitumab (AMG 479), a human MAB against IGF1R, may have antitumor activity in this setting. We performed a two-cohort phase II study of ganitumab in patients with metastatic progressive carcinoid or pancreatic NETs (pNETs). This open-label study enrolled patients (≥18 years) with metastatic low- and intermediate-grade carcinoid or pNETs. Inclusion criteria included evidence of progressive disease (by Response Evaluation Criteria in Solid Tumors (RECIST)) within 12 months of enrollment, ECOG PS 0-2, and fasting blood sugar <160  mg/dl. Prior treatments were allowed and concurrent somatostatin analog therapy was permitted. The primary endpoint was objective response. Secondary endpoints included overall survival (OS), progression-free survival (PFS), and safety. Sixty patients (30 carcinoid and 30 pNETs) were treated with ganitumab 18  mg/kg every 3 weeks, among whom 54 patients were evaluable for survival and 53 patients for response. There were no objective responders by RECIST. The median PFS duration was 6.3 months (95% CI, 4.2-12.6) for the entire cohort; 10.5 months for carcinoid patients, and 4.2 months for pNET patients. The OS rate at 12 months was 66% (95% CI, 52-77%) for the entire cohort. The median OS has not been reached. Grade 3/4 AEs were rare and consisted of hyperglycemia (4%), neutropenia (4%), thrombocytopenia (4%), and infusion reaction (1%). Although well tolerated, treatment with single-agent ganitumab failed to result in significant tumor responses among patients with metastatic well-differentiated carcinoid or pNET.

A multicenter phase II trial of single-agent cetuximab in advanced esophageal and gastric adenocarcinoma.

BACKGROUND: Epidermal growth factor receptor (EGFR) is overexpressed in a significant proportion of esophageal and gastric carcinomas. Although previous studies have examined tyrosine kinase inhibitors of EGFR, there remains limited data regarding the role of EGFR-directed monoclonal antibody therapy in these malignancies. We carried out a multi-institutional phase II study of cetuximab, a monoclonal antibody against EGFR, in patients with unresectable or metastatic esophageal or gastric adenocarcinoma. PATIENTS AND METHODS: Thirty-five patients with previously treated metastatic esophageal or gastric adenocarcinoma were treated with weekly cetuximab, at an initial dose of 400 mg/m(2) followed by weekly infusions at 250 mg/m(2). Patients were followed for toxicity, treatment response, and survival. RESULTS: Treatment with cetuximab was well tolerated; no patients were taken off study due to drug-related adverse events. One (3%) partial treatment response was noted. Two (6%) patients had stable disease after 2 months of treatment. Median progression-free survival and overall survival were 1.6 and 3.1 months, respectively. CONCLUSION: Although well tolerated, cetuximab administered as a single agent had minimal clinical activity in patients with metastatic esophageal and gastric adenocarcinoma. Ongoing studies of EGFR inhibitors in combination with other agents may define a role for these agents in the treatment of esophageal and gastric cancer.

Outer segment phagocytosis by cultured retinal pigment epithelial cells requires Gas6.

The function and viability of vertebrate photoreceptors requires the daily phagocytosis of photoreceptor outer segments (OS) by the adjacent retinal pigment epithelium (RPE). We demonstrate here a critical role in this process for Gas6 and by implication one of its receptor protein tyrosine kinases (RTKs), Mertk (Mer). Gas6 specifically and selectively stimulates the phagocytosis of OS by normal cultured rat RPE cells. The magnitude of the response is dose-dependent and shows an absolute requirement for calcium. By contrast the Royal College of Surgeons (RCS) rat RPE cells, in which a mutation in the gene Mertk results in the expression of a truncated, non-functional receptor, does not respond to Gas6. These data strongly suggest that activation of Mertk by its ligand, Gas6, is the specific signaling pathway responsible for initiating the ingestion of shed OS. Moreover, photoreceptor degeneration in the RCS rat retina, which lacks Mertk, and in humans with a mutation in Mertk, strongly suggests that the Gas6/Mertk signaling pathway is essential for photoreceptor viability. We believe that this is the first demonstration of a specific function for Gas6 in the eye.

The effects of colchicine treatment on wound healing in a caustic murine injury model.

OBJECTIVE: The present study determined the effects of colchicine on wound repair in a murine model of dermal chemical injury. METHODS: Standardized 4.15 cm2 circular lesions were induced on the dorsum of adult male mice with NaOH. Five minutes of IN or 3N caused lesions of graded depth. Mice received colchicine (1 mg/kg) or phosphate-buffered saline intraperitoneally in equivalent volumes. Treatment began immediately postinjury and was continued on an alternating day schedule for 14 days. Wound size was measured every third day postinjury. On day 15 postinjury, wounds were histologically graded for depth of injury, degree of fibrosis, inflammatory cell response, and revascularization. All histological determinations and wound measurements were performed in a blinded fashion. RESULTS: All mice had a similar initial wound size and completed the experimental protocol. In dermal wounds of superficial depth, colchicine-treated mice (n = 20) had a larger wound size during days 6 through 9 of the experimental trial when compared to phosphate-buffered saline-treated mice (n = 18). In the deeper wounds, there were no significant differences in wound size between colchicine and phosphate-buffered saline-treated groups. Colchicine (n = 54) did not affect the degree of fibrosis at all depths of injury vs phosphate-buffered saline treatment in mice (n = 55). The degree of wound revascularization was less in colchicine-treated mice (n = 54) than phosphate-buffered saline-treated mice (n = 55). CONCLUSION: Colchicine did not improve wound healing in an alkaline-induced dermal injury.

Use-dependent decline of paired-pulse facilitation at Aplysia sensory neuron synapses suggests a distinct vesicle pool or release mechanism.

We have characterized paired-pulse facilitation at Aplysia sensory neuron-to-motoneuron synapses. This simple form of very short-term synaptic plasticity displayed an unusual feature: it decreased dramatically with repeated testing. Synaptic depression at these synapses and this use-dependent decrease in paired-pulse facilitation occurred independently of each other. Paired-pulse facilitation was inversely correlated with the size of the initial synaptic connection and was absent at stronger synapses. The use-dependent decrease in paired-pulse facilitation occurred at the same rate at large synapses as at small synapses, although the initial paired-pulse facilitation at large synapses was substantially smaller. Rates of synaptic depression were also independent of initial synaptic strength. Paired-pulse facilitation was blocked by presynaptic EGTA injection, but not by postsynaptic EGTA or BAPTA injection. These results indicate that presynaptic Ca2+ influx plays a critical role in paired-pulse facilitation. However, the persistence of the decrease in paired-pulse facilitation for longer than 15 min suggests that Ca2+ from the first paired action potential produces facilitation via a modulatory mechanism rather than by summating with Ca2+ influx during the second paired action potential in activating the Ca2+ binding sites that initiate exocytosis. This modulatory mechanism may not involve protein phosphorylation because paired-pulse facilitation was unaffected by the protein kinase inhibitors H7 and KN-62. These findings further suggest that release by the second paired action potential occurs at sites distinct from those that mediate release by the first action potential.

Sequence-dependent interactions between transient calcium and transmitter stimuli in activation of mammalian brain adenylyl cyclase.

Recent evidence implicates Ca2+/CaM-sensitive adenylyl cyclase (AC) as a molecular coincidence detector for temporally paired stimuli during associative learning. During conditioning in Aplysia, AC is optimally activated when Ca2+ influx, the cellular signal for the conditioned stimulus (CS), precedes binding of modulatory transmitter, the cellular signal for the unconditioned stimulus (US). This sequence preference of the AC for Ca2+-before-transmitter, parallels the CS-preceding-US pairing requirement of classical conditioning. In this study, we have examined the response of AC from rat cerebellum to brief exposures to Ca2+ and to transmitter in a perfused membrane assay. We observed modest synergism between Ca2+ and transmitter in activating AC. Activation was more effective when a Ca2+ stimulus immediately preceded a transmitter stimulus than when the two stimuli were delivered in the reverse order. Thus, rat cerebellar AC displayed a sequence preference for optimal activation by paired stimuli similar to that observed in Aplysia; this sequence dependence could contribute to the CS-US sequence requirement observed in most mammalian classical conditioning paradigms.

Persistence of the interaction of calmodulin with adenylyl cyclase: implications for integration of transient calcium stimuli.

Ca2+/calmodulin-sensitive adenylyl cyclase plays a role in several forms of synaptic plasticity and learning. To understand how cellular signals from neuronal activity during behavioral stimuli might be integrated by adenylyl cyclase, we have characterized the response of type I adenylyl cyclase to transient Ca2+ stimuli. Stimulation by a several second Ca2+ stimulus is delayed, rising to a peak after the Ca2+ stimulus has ended. We attempted to identify the site of the persistent Ca2+ signal that enabled adenylyl cyclase stimulation to increase after free Ca2+ had declined. Free calmodulin itself displayed no persistent activation by Ca2+ and was unable to activate adenylyl cyclase if exposed to low Ca2+ solution <1 s before reaching adenylyl cyclase. In contrast, activation of the calmodulin-adenylyl cyclase complex persisted for seconds after Ca2+ stimulus. Activation decayed with a time constant of 6 or 13 s depending on assay conditions. These results suggest that the calmodulin-adenylyl cyclase complex can serve as a site of cellular memory for a Ca2+ transient that has ended even before adenylyl cyclase is fully activated.

The effect of the neuropeptide FMRFamide on Aplysia californica siphon motoneurons involves multiple ionic currents that vary seasonally.

The molluscan neuropeptide FMRFamide has a number of inhibitory actions on the sensory neurons and motoneurons mediating the defensive gill and siphon withdrawal reflex pathway of Aplysia californica. Exogenous application of FMRFamide has a biphasic, dual-polarity effect on the majority of LFS siphon motoneurons, causing a transient depolarization followed by a prolonged hyperpolarization. FMRFamide induces this response in LFS neurons by causing an increase in multiple ionic currents, including a transient Na+ current, a slow prolonged Na+ current, a 4-aminopyridine (4-AP)-sensitive K+ current and a 4-AP-insensitive K+ current. We have found that a subset of LFS neurons exhibits an exclusively excitatory, biphasic response to FMRFamide, consisting of a transient depolarization followed by a prolonged depolarization of reduced magnitude. Over a period of 29 months, we consistently observed an increase in the incidence of the exclusively excitatory response during the summer months (June to September). From October to May, we observed an exclusively excitatory response to FMRFamide in 19 % of LFS neurons; yet, in the summer months, 51 % of LFS neurons exhibited this response pattern. We compared the ionic basis of the exclusively excitatory response to FMRFamide with the ionic mechanisms mediating the more frequently observed excitatory/inhibitory response. The exclusively excitatory response involves three of the same ionic components as the more typical excitatory/inhibitory response, including the activation of a transient Na+ current, a slow prolonged Na+ current and a 4-AP-insensitive K+ current. The principal difference between the two response types is that FMRFamide fails to activate a 4-AP-sensitive K+ current in those LFS neurons that exhibit an exclusively excitatory response to the peptide. In addition, LFS neurons with an exclusively excitatory response tend to show a coordinated increase in the magnitude of the inward current component of the FMRFamide response. Together, these changes during the summer months may enable this modulatory peptide to bring LFS neurons to suprathreshold levels of activity for eliciting a siphon withdrawal and should substantially alter the neuromodulatory effects of the peptide.

Changes in the parous rat mammary gland environment are involved in parity-associated protection against mammary carcinogenesis.

Parity in rats results in protection from methylnitrosourea (MNU)-induced mammary cancer. Our goal was to determine if systemic alterations in the mammary gland environment after a full-term pregnancy rendered the parous rat an inadequate host for promotion of initiated mammary epithelial cells to become cancerous. Lewis rat MNU-treated mammary epithelial cells were transplanted into uniparous (UP), age-matched virgin (AMV) (both 130-150 d), or young virgin (YV) (50-60 d) syngeneic hosts to examine if differences in the systemic environments of the three hosts had an effect on hyperplasia and cancer formation. More transplants in YV and AMV hosts contained hyperplasias and adenocarcinomas as compared to transplants in UP hosts. In addition, UP host transplants had significantly fewer numbers of hyperplastic lesions than transplants from the virgin hosts. The evidence presented here shows that the uniparous host environment is less supportive than that of the virgin host for hyperplasia and cancer development.

Analysis of sequence-dependent interactions between transient calcium and transmitter stimuli in activating adenylyl cyclase in Aplysia: possible contribution to CS--US sequence requirement during conditioning.

An important recent insight in a number of neurobiological systems is that during learning, individual dually regulated proteins with associative properties function as critical sites of stimulus convergence. During conditioning in Aplysia, the Ca2+ /calmodulin-sensitive adenylyl cyclase (AC) in mechanosensory neurons serves as a molecular site of interaction between Ca2+ and serotonin [5-hydroxytryptamine (5-HT)]-two signals that represent the CS and US in these cells. Conditioning requires that the CS and US be paired within a narrow time window and in the appropriate sequence. AC shows an analogous sequence preference: It is more effectively activated when a pulse of Ca2+ precedes a pulse of 5-HT than when the 5-HT precedes Ca2+. One mechanism that contributes to this sequence preference is that Ca2+/calmodulin binding to AC accelerates the rate of AC activation by receptor-Gs. We have identified two additional properties of AC activation that would cause pairing with Ca2+ preceding 5-HT to be more effective than simultaneous pairing or pairing with the reciprocal sequence: (1) Activation of Aplysia AC by a Ca2+ pulse rose with a delay compared with activation by a 5-HT pulse. (2) A late pulse of Ca2+, which arrived after 5-HT, acted, via calmodulin, to accelerate the decay of AC activation by receptor-Gs. Together, these activation properties of AC may contribute to the CS-US sequence requirement of classical conditioning.

Further studies on the identification of the phagocytosis receptor of rat retinal pigment epithelial cells.

We have previously produced a polyclonal antiserum (R1S5) against a plasma membrane-enriched fraction of rat retinal pigment epithelial (RPE) cells which inhibits the phagocytosis of photoreceptor outer segments (OS) by these cells. This antiserum has now been used to purify a subset of RPE membrane glycoproteins. Using a combination of lectin affinity chromatography, and chromatography on an affinity column made with R1S5-IgG, we have enriched an RPE membrane extract about 100-fold. This enriched extract contains only 12 components, all of which are glycoproteins, and retains the ability to adsorb out the inhibitory activity of antiserum R1S5. This shows that one or more of these glycoproteins recognizes an inhibitory IgG in R1S5 and suggests that one or more of these glycoproteins may participate in the phagocytosis of OS by RPE cells, possibly as the phagocytosis receptor. We have performed N-terminal microsequencing of seven of these glycoproteins: four of the seven, with Mrs of 34, 36, 51 and 55 kDa, show no sequence homology to any known proteins.

Carbachol does not correct the defect in the phagocytosis of outer segments by Royal College of Surgeons rat retinal pigment epithelial cells.

PURPOSE: To investigate the effect of carbachol on the phagocytosis of photoreceptor outer segments (OS) in cultures of normal Long-Evans and dystrophic Royal College of Surgeons (RCS) rat retinal pigment epithelial (RPE) cells. METHODS: Retinal pigment epithelial cells from normal and RCS rats were grown in tissue culture. On reaching confluence, they were presented with OS suspended in Krebs-Henseleit buffer in the presence or absence of carbachol and LiCl. The number of bound and ingested OS was quantitated using double immunofluorescence staining. RESULTS: LiCl inhibited the ingestion of OS by more than 90% but had no effect on the binding of OS by Long-Evans RPE cells. The addition of carbachol further reduced OS ingestion. Carbachol alone decreased OS ingestion by normal RPE cells by 30% but had no effect on OS binding. The effect of LiCl and carbachol on RCS RPE cells was similar to their effect on normal RPE cells. CONCLUSIONS: Carbachol does not increase OS phagocytosis in normal or RCS rat RPE cells. The phagocytic defect in RCS rat RPE cannot be reversed or overcome by stimulation of the IP3 pathway by carbachol. LiCl strongly inhibits the ingestion of OS by normal and by RCS RPE cells, and this effect is enhanced by carbachol.