Regionally compartmentalized resident memory T cells mediate naturally acquired protection against pneumococcal pneumonia.

As children age, they become less susceptible to the diverse microbes causing pneumonia. These microbes are pathobionts that infect the respiratory tract multiple times during childhood, generating immunological memory. To elucidate mechanisms of such naturally acquired immune protection against pneumonia, we modeled a relevant immunological history in mice by infecting their airways with mismatched serotypes of Streptococcus pneumoniae (pneumococcus). Previous pneumococcal infections provided protection against a heterotypic, highly virulent pneumococcus, as evidenced by reduced bacterial burdens and long-term sterilizing immunity. This protection was diminished by depletion of CD4+ cells prior to the final infection. The resolution of previous pneumococcal infections seeded the lungs with CD4+ resident memory T (TRM) cells, which responded to heterotypic pneumococcus stimulation by producing multiple effector cytokines, particularly interleukin (IL)-17A. Following lobar pneumonias, IL-17-producing CD4+ TRM cells were confined to the previously infected lobe, rather than dispersed throughout the lower respiratory tract. Importantly, pneumonia protection also was confined to that immunologically experienced lobe. Thus regionally localized memory cells provide superior local tissue protection to that mediated by systemic or central memory immune defenses. We conclude that respiratory bacterial infections elicit CD4+ TRM cells that fill a local niche to optimize heterotypic protection of the affected tissue, preventing pneumonia.

An Exploration of Family and Juvenile Justice Systems to Reduce Youth HIV/STI Risk.

Using in-depth interviews with 20 probation youth (60% female; 35% white; 30% Hispanic; mean age 15years, range=13-17), their caregivers (100% female; mean age 44years, range=34-71) and 12 female probation officers (100% white; mean age 46years, range=34-57), we explored how family and probation systems exacerbate or mitigate sexual risk. We conducted thematic analyses of interviews, comparing narratives of families of sexually risky (n=9) versus non-sexually risky (n=11) youth. Family functioning differed by youth sexual risk behavior around quality of relationships, communication, and limit-setting and monitoring. The involvement of families of sexually risky youth in probation positively influenced family functioning. Data suggest these families are amenable to intervention and may benefit from family-based HIV/STI interventions delivered in tandem with probation.

Validation of peptide mapping with electrospray mass spectrometry for recombinant proteins of biopharmaceutical interest and its applications as an identity test and a characterization tool.

In this paper, the steps required to validate a liquid chromatography peptide mapping method with mass spectrometric detection (LC-MS) for use as an identity test and characterization tool are presented. All aspects of peptide mapping are evaluated and optimized, including protein sample preparation (protein reduction, alkylation and enzymatic digestion), high performance liquid chromatography (HPLC) separation of the resulting peptides, and the use of a mass spectrometric detection. In addition, the validation of a single quadruple MS detector is described and the implementation of on-line electrospray ionization MS (ESI-MS) as an adjunct detector to support the investigation of peak differences is presented. Applications of peptide mapping with tandem MS using an electrospray ion-trap instrument throughout the biopharmaceutical product development cycle are discussed, including assessing protein product heterogeneity derived from post-translational modifications (e.g. multiple N- or C-termini, deamidation, oxidation and glycosylation) and protein degradation.

Categorical and prolonged potentials are evoked when brief, intermediate-intensity flashes stimulate horseshoe crab lateral eye photoreceptors during octopamine neuromodulation.

Octopamine, a major efferent neurotransmitter in the lateral eye of the horseshoe crab (Limulus polyphemus), has previously been shown to modulate photoreceptor responses evoked by long flashes. Quantification of these data indicates that this modulation produced a genuine increase in sensitivity to light which cannot be entirely due to an increase in optical efficiency consequent on an anatomical alteration. Other previous studies demonstrated that extrinsic current can modulate Limulus lateral eye photoreceptor cells by inducing a bistable membrane potential with two distinct states. The present study was therefore undertaken to find out if octopamine could modulate visual responses by inducing prolonged and bistable polarization shifts similar to those demonstrated in several other neural systems. Intracellular microelectrodes were used to execute an electrophysiological study of the receptor potentials evoked in the lateral eye of Limulus when brief (20-ms) flashes were delivered while 50 microM octopamine perfused dark-adapted photoreceptors. The combined chemical and optical stimuli prolonged photoreceptor responses to light to the degree that they often exceeded the duration of the brief stimulus by hundreds of milliseconds. Moreover, these prolonged potentials were clearly bistable because they were categorical--either a prolongation was perceptually clear-cut and present or it was not, with no intermediate patterns being observed. During seawater control perfusions, such prolongations were absent. This appears to be the first demonstration of such categorical and prolonged potentials in a photoreceptor neuron. This finding particularly suggests that efferent-driven neuromodulation can enable the development of a persisting short-term representation of a brief stimulus, with this representation being retained at the most distal possible neural site.

Dissociating sensory and cognitive contributions to visual persistence I. Photoreceptor response duration as a function of flash intensity, adaptation state, and candidate code.

Numerous careful behavioral studies of visual persistence have reported a variety of apparently contradictory effects. Variation of flash intensity has particularly been found to have both direct and inverse effects on subjective duration. This conflict has been addressed by theories which contain both sensory and cognitive components. Depending on the weight given to these components, one obtains theories which emphasize intensity dependence or task dependence. Few comparably detailed physiological studies of persistence exist. To clarify the issues raised by these theories, we examined the responses evoked in the model photoreceptor of the Limulus lateral eye. To explore the role of sensory variables, we manipulated adaptation state and flash intensity. To explore cognitive variables, the durations of the photoreceptor potentials (RPs) evoked in this model system were assessed by a mutually complementary and complete set of candidate sensory codes. Accordingly, sharp microelectrodes were used to record RPs intracellularly from single photoreceptor cells in response to 40-ms flashes whose intensity was varied over at least 3.6 log units. Two light adaptation states were used which differed in sensitivity by 3.5 log units. This model system made it possible to employ stringent objective assessments of data quality which ensured that only cells which had remained stable for several hours contributed to the present data. A variety of code-dependent trends were found: direct, inverse, invariant, and U-shaped trends related flash intensity to RP duration, while adaptation state interacted with some of these trends. Only some of the expectations which had generated this research were qualitatively corroborated and numerous quantitative discrepancies were found between data and theory. While caution is necessary when generalizing from neural responses to perception, these data indicate that two major gaps now exist in this field. First, both task and stimulus variables need to be exhaustively explored in more complete behavioral experiments. The present data make it more likely that sensory models and cognitive models simply address different aspects of the same phenomenon. Second, similarly detailed questions need to be posed to more central neural loci, particularly to those in the various visual cortices.

Dissociating sensory and cognitive contributions to visual persistence II. Photoreceptor integration of flash pairs as a function of interflash interval, intensity, integration site, and candidate code.

Perceived duration can be assessed behaviorally by adjusting the interval between two flashes so that an observer just perceives a certain relation between them. In such studies, the cognitive characteristics of the required relation necessarily interact with the sensory characteristics of the responses evoked by the two flashes. To dissociate the contributions of these two factors, we executed a physiological study which yielded more complete information on the role of each factor in two paradigms which have been used to characterize perceived duration behaviorally, namely the persistence-of-form design and the successive field design. The effect of sensory manipulations have yielded particularly problematic results in these two paradigms because opposite trends were found when intensity was varied. Intracellular recordings were therefore taken from photoreceptor cells exposed to procedural manipulations which match the sensory and cognitive variations employed in behavioral paradigms. The sensory variables of flash intensity, state of adaptation, and flash interval were explored with some completeness. Cognitive factors were assessed in two ways. First, the contribution of the neural site of sensory integration was determined by making a clear distinction between data collected when all stimuli affect the same receptors versus data collected when different stimuli affect different receptors. Second, the consequences of arbitrary choices of candidate code and dependent variable were also explored. When so organized, the physiological data provide a coherent basis for harmonizing apparently contradictory behavioral results because they qualitatively paralleled the behavioral data's complex dependence on intensity and interval. In particular, both direct and inverse dependencies of response duration on intensity exist in both physiology and behavior with the exact nature of the trend depending as much on the cognitive analysis of the neural responses as on their dynamics and energetics. Further, large quantitative differences were found which also were an expression of the different ways in which the two behavioral paradigms affect receptor potentials.

Elevation of serum interleukin 8 levels in acetaminophen overdose in children and adolescents.

BACKGROUND: Elevations of inflammatory cytokines have been reported in animal models of acetaminophen (INN, paracetamol) toxicity. In addition, interleukin 8, a chemokine, has been found to be elevated in toxin-associated hepatic disease (ie, acute alcoholic hepatitis). The purpose of this study was to measure serum cytokine levels in children and adolescents with acetaminophen overdose and to evaluate relationships between cytokine elevation and hepatotoxicity. METHODS: Serum levels of tumor necrosis factor alpha, interleukin 1beta, interleukin 6, interleukin 8, and interleukin 10 were measured by ELISA in children and adolescents (n = 35) with acetaminophen overdose. Peak cytokine levels were examined relative to biochemical evidence of hepatocellular injury, nomogram risk assessment, and prothrombin time. RESULTS: Five patients had aspartate aminotransferase or alanine aminotransferase levels >1000 IU/L, and 4 patients had aspartate aminotransferase or alanine aminotransferase levels > or =100 IU/L and < or =1000 IU/L. No elevations of tumor necrosis factor alpha or interleukin 1beta were detected. Peak interleukin 8, but not interleukin 6 or interleukin 10, correlated with hepatotoxicity (Mann-Whitney exact test, P <.001). The peak interleukin 8 level was greater in patients at high risk by the nomogram combined with those presenting at >15 hours, as compared with other patients (Mann-Whitney U test, P <.01). The interleukin 8 level peaked before aspartate aminotransferase or alanine aminotransferase in 5 of the 9 patients with hepatotoxicity. In addition, interleukin 8 concentrations of >20 pg/mL were associated with peak prothrombin time values (Mann-Whitney exact test, P <.015). CONCLUSIONS: Interleukin 8 elevation in patients with acetaminophen hepatotoxicity corresponds with other common clinical measures that are predictive of hepatocellular injury. Further study is warranted to evaluate possible mechanistic relationships between inflammatory cytokines and acetaminophen hepatotoxicity in children and adults.

Measurement of acetaminophen-protein adducts in children and adolescents with acetaminophen overdoses. .

Acetaminophen-protein adducts are biomarkers of acetaminophen toxicity present in the centrilobular region of the liver of laboratory animals following the administration of toxic doses of acetaminophen. These biomarkers are highly specific for acetaminophen-induced hepatic injury and correlate with hepatic transaminase elevation. The objective of this prospective, multicenter study was to evaluate the clinical application of the measurement of acetaminophen-protein adducts in pediatric acetaminophen overdose patients. Serum samples were obtained from 51 children and adolescents with acetaminophen overdose at the time of routine blood sampling for clinical monitoring. Six subjects developed "severe" hepatotoxicity (transaminase elevation > 1,000 IU/L), and 6 subjects had transaminase elevation of 100 to 1,000 IU/L. Acetaminophen-protein adducts were detected in the serum of only 1 study subject, a patient with marked transaminase elevation (> 6,000 IU/L) and high risk for the development of hepatotoxicity according to the Rumack nomogram. While this study provides further support for the occurrence of covalent binding of acetaminophen to hepatic protein in humans following acetaminophen overdose, the detection of acetaminophen-protein adducts in serum with the current methodology requires significant biochemical evidence of hepatocellular injury.

Theophylline toxicokinetics in premature newborns.

BACKGROUND: While cytochrome P4501A2 is the primary pathway for theophylline (aminophylline ethylenediamine) metabolism in adults, it is developmentally immature in the newborn. OBJECTIVE: To report the developmental differences in theophylline toxicokinetics of neonates. DESIGN: Case series. Three premature neonates received inadvertent intravenous overdoses of theophylline for apnea of prematurity while in newborn intensive care. Maximum serum concentrations ranged from 55 to 123 mg/L. Theophylline-derived caffeine levels plateaued at 8.4 to 13 mg/L and did not decline during the sampling period. All newborns experienced sinus tachycardia and agitation. Sequential theophylline and caffeine serum levels were obtained periodically for 62 to 100 hours. In contrast to older children and adults, in whom theophylline disposition follows zero-order kinetics at high concentrations, a monoexponential function best described theophylline elimination in the premature newborn, with half-lives ranging from 24.7 to 36.5 hours and estimated clearance from 0.02 to 0.05 L/kg per hour. These values are consistent with those previously reported in neonates. All patients were treated with supportive care without invasive procedures. No seizures or apparent sequelae occurred. CONCLUSION: Developmental differences in the balance between nonrenal (ie, metabolic) and renal elimination pathways produce the unique toxicokinetics of theophylline in the neonate.

Contribution of maternal smoking during pregnancy and lead exposure to early child behavior problems.

Maternal smoking during pregnancy elevates risk for later child behavior problems. Because prior studies considered only Western settings, where smoking co-occurs with social disadvantage, we examined this association in Yugoslavia, a different cultural setting. Mothers enrolled in pregnancy as the low-exposure group in a prospective study of lead exposure were interviewed about health, including smoking history. A total of 199 children were assessed on the Child Behavior Checklist (CBCL) at ages 4, 4 1/2, and 5 years. Average cumulative blood lead (BPb) was determined from serial samples taken biannually since delivery. Longitudinal analyses were derived from 191 children with available data on behavior and covariates. Smoking was unrelated to social adversity. Controlling for age, gender, birthweight, ethnicity, maternal education, and Home Observation for Measurement of the Environment (HOME) Acceptance, smoking was associated with worse scores on almost all subscales; BPb concentration was related to small increases in the Delinquency subscale. Daughters of smokers received significantly higher scores on Somatic Complaints compared to daughters of nonsmokers, consistent with other work relating biological factors and internalizing problems in young girls. Because the present smoking/child behavior associations persist after control for individual and social factors also related to behavior problems, possible biological mediators are considered.

Methodology, inference and causation: environmental lead exposure and childhood intelligence.

Kaufman's critique of the literature on the associations between lead exposure and child intelligence raises important methodological and inferential points. We address the concerns he raises regarding measuring known and unknown confounders, statistical modeling, reverse causality and quality control. Mismeasurement of potential confounders of the lead-IQ relationship, such as parenting skills, parental intelligence, maternal smoking during pregnancy, or otitis media can either strengthen or weaken the estimated association between exposure and child intelligence. Despite some variability in design and measurement, a series of comprehensive prospective investigations in varied populations, by different sets of investigators, provided consistent replication; taken together these studies point to the conclusion that lead exposure has adverse consequences for child development, and that the deficits are likely to be small in comparison to the contribution of measured social factors.

The Yugoslavia Prospective Lead Study: contributions of prenatal and postnatal lead exposure to early intelligence.

To investigate associations between the timing of lead (Pb) exposure on early intelligence, we examined the results of psychometric evaluations at ages 3, 4, 5, and 7 years, from 442 children whose mothers were recruited during pregnancy from a smelter town and a non-lead-exposed town in Yugoslavia. We compared the relative contribution of prenatal blood lead (BPb) with that of relative increases in BPb in either the early (0-2 years) or the later (from 2 years on) postnatal period to child intelligence measured longitudinally at ages 3 and 4 (McCarthy GCI), 5 (Wechsler Preschool and Primary Scale of Intelligence-Revised, WPPSI-R IQ), and 7 (Wechsler Intelligence Scale for Children-version III, WISC-III IQ), controlling for: Home Observation for Measurement of the Environment (HOME) quality; maternal age, intelligence, education, and ethnicity; and birthweight and gender. Elevations in both prenatal and postnatal BPb were associated with small decrements in young children's intelligence.

Lead exposure and motor functioning in 4(1/2)-year-old children: the Yugoslavia prospective study.

OBJECTIVE: To investigate associations between lead exposure and early motor development. STUDY DESIGN: We conducted standardized assessments of motor function (Bruininks-Oseretsky Test of Motor Proficiency and Beery Developmental Test of Visual-Motor Integration) at age 54 months in 283 children whose mothers were recruited in pregnancy from a smelter town and a non-lead-exposed town in Yugoslavia and who have been monitored twice yearly since birth. Blood lead concentration (BPb) was summarized in a measure reflecting the average of the child's semiannual serial log BPbs through 54 months. RESULTS: Multiple regression showed that taken together, anthropometric measures (birth weight, body mass index) and markers of a stimulating and organized home life (HOME scale, parental education and intelligence, availability of siblings) explained a significant 10% to 18% of the variance in motor functioning. Beyond these contributions, BPb was significantly associated with poorer fine motor and visual motor function but was unrelated to gross motor coordination. CONCLUSIONS: Modest associations between early lead exposure and fine motor and visual motor functioning appear even after statistical adjustment is done for other contributors to motor development. Associations with BPb are specific to these areas of motor skill; gross motor development was unaffected.

Acetaminophen intoxication during treatment: what you don't know can hurt you.

For over two decades, pediatricians have been made aware of the potential risk associated with the acute ingestion of large single and/or multiple doses of acetaminophen (APAP). Clearly, APAP-induced hepatotoxicity remains as a recognized medical emergency which, when treated promptly with appropriate gastrointestinal decontamination and when indicated, with the antidote N-acetylcysteine, has a uniformly good clinical outcome. Recently, the hepatotoxic potential associated with "therapeutic" APAP administration has been brought to the attention of the pediatric community. This review explores the issue of APAP toxicity with therapeutic intent by examining both the clinical literature and also, relevant information concerning the basic pharmacology and toxicology of this old and widely used nonprescription drug. A "risk profile" is developed with regard to factors that may predispose infants and children to this iatrogenic form of toxicity so that the awareness of physicians and other caregivers (including parents) can be heightened and preventative education administered. As is true for most all potentially beneficial medicines used in pediatrics, awareness of the actual amount of drug received from all sources and caution to not exceed the age-appropriate dosing guidelines (i.e., both amount and duration) contained in the approved labeling for all products containing APAP will insure safe and effective therapy.

Memory and anxiety in prepubertal boys at risk for delinquency.

OBJECTIVE: To examine the association between memory and anxiety symptoms in young urban-dwelling boys. METHOD: A series of 111 boys, aged 7 to 11 years, at risk for disruptive psychopathology received standardized assessments of psychopathology and neuropsychological abilities, including verbal and design memory ability. While neuropsychological ability was rated at an initial study wave, psychopathology was rated at both an initial and a follow-up study wave, separated by approximately 18 months. RESULTS: Anxiety symptoms were more strongly correlated with poor memory ability than with reduced intelligence. Disruptive symptoms, in contrast, were more strongly correlated with reduced intelligence than with poor memory ability. Finally, boys with an anxiety disorder exhibited reduced memory abilities relative to other boys in the sample. Relationships generally appeared strongest in longitudinal analyses, such that poorer memory ability at study intake predicted increased anxiety at follow-up. CONCLUSIONS: Anxiety is associated with reduced memory ability in young urban boys at risk for disruptive psychopathology.

Dichotic listening deficits and the prediction of substance use in young boys.

OBJECTIVE: Prior studies note relationships among verbal deficits, disruptive psychopathology, and substance use. The current study examines the relationship between verbal deficits, assessed through a dichotic listening test, and children's substance use. METHOD: A series of 87 young boys was prospectively followed over a 1- to 2-year period. A prior study in these boys noted a cross-sectional relationship between disruptive psychopathology and deficits on a dichotic consonant-vowel listening test. The current study examines the predictive relationship between this language-related deficit at one study wave and substance use assessed during a follow-up study wave. RESULTS: Reduced right ear accuracy, reflecting a deficit in left hemisphere processing ability, predicted substance use at follow-up. This association was independent of any other predictors, including cognitive or behavioral indices of substance use risk. CONCLUSIONS: A lateralized deficit in verbal processing on a dichotic listening task predicts change in substance use by follow-up. Findings are consistent with other evidence linking early childhood lateralization abnormalities to development of disruptive psychopathology.

Intravenous midazolam for sedation of children undergoing procedures: an analysis of age- and procedure-related factors.

OBJECTIVE: This study was performed to determine the doses of midazolam used for sedation during procedures in children, and the frequency of adverse events. METHODS: We performed a retrospective analysis of data collected for a prospective study of flumazenil in children who had received midazolam for a procedure (n = 91, 1-17 years). RESULTS: Practitioners used a wide range of total midazolam doses (0.03-0.6 mg/kg); mean doses ranged from 0.09 +/- 0.06 mg/kg in adolescents to 0.26 +/- 0.13 mg/kg in toddlers (P < 0.001). Opioids were also used in 84% of patients. Twenty-six percent of children with normal lungs, most of whom had received relatively high opioid doses, developed decreased oxygen saturation (as low as 65%) after sedation. Other adverse events included airway obstruction (n = 3) and vomiting (n = 1). CONCLUSIONS: The frequent choice of midazolam, usually combined with an opioid, indicates its wide acceptance. Midazolam doses were inversely related to age. The presence of vomiting, airway obstruction, and decreased oxygen saturation underlines the importance of appropriate personnel, equipment, and monitors during sedation.

Darryl, a cartoon-based measure of cardinal posttraumatic stress symptoms in school-age children.

OBJECTIVES: This report examines the reliability and validity of Darryl, a cartoon-based measure of the cardinal symptoms of posttraumatic stress disorder (PTSD). METHODS: We measured exposure to community violence through the reports of children and their parents and then administered Darryl to a sample of 110 children aged 7 to 9 residing in urban neighborhoods with high crime rates. RESULTS: Darryl's reliability is excellent overall and is acceptable for the reexperiencing, avoidance, and arousal subscales, considered separately. Child reports of exposure to community violence were significantly associated with child reports of PTSD symptoms. CONCLUSIONS: Darryl possesses acceptable psychometric properties in a sample of children with frequent exposure to community violence.