DNA-based species detection capabilities using laser transmission spectroscopy.

Early detection of invasive species is critical for effective biocontrol to mitigate potential ecological and economic damage. Laser transmission spectroscopy (LTS) is a powerful solution offering real-time, DNA-based species detection in the field. LTS can measure the size, shape and number of nanoparticles in a solution and was used here to detect size shifts resulting from hybridization of the polymerase chain reaction product to nanoparticles functionalized with species-specific oligonucleotide probes or with the species-specific oligonucleotide probes alone. We carried out a series of DNA detection experiments using the invasive freshwater quagga mussel (Dreissena bugensis) to evaluate the capability of the LTS platform for invasive species detection. Specifically, we tested LTS sensitivity to (i) DNA concentrations of a single target species, (ii) the presence of a target species within a mixed sample of other closely related species, (iii) species-specific functionalized nanoparticles versus species-specific oligonucleotide probes alone, and (iv) amplified DNA fragments versus unamplified genomic DNA. We demonstrate that LTS is a highly sensitive technique for rapid target species detection, with detection limits in the picomolar range, capable of successful identification in multispecies samples containing target and non-target species DNA. These results indicate that the LTS DNA detection platform will be useful for field application of target species. Additionally, we find that LTS detection is effective with species-specific oligonucleotide tags alone or when they are attached to polystyrene nanobeads and with both amplified and unamplified DNA, indicating that the technique may also have versatility for broader applications.

Effect of intracranial bleeds on the neurocognitive, academic, behavioural and adaptive functioning of boys with haemophilia.

Brain insults are a risk factor for neuropsychological and academic deficits across several paediatric conditions. However, little is known about the specific effects of intracranial haemorrhage (ICH) in boys with haemophilia. The study compared neurocognitive, academic and socio-emotional/behavioural outcomes of boys with haemophilia with and without a history of ICH. Of 172 consecutive patients seen at a Pediatric Comprehensive Care Hemophila Centre, 18 had a history of ICH. Sixteen boys between the ages of 3 and 17 years were available for study and were matched to controls with haemophilia of the same age and disease severity and on the basis of maternal education. Groups were compared on neuropsychological and academic outcomes. Attention, socio-emotional function and executive skills were compared using data from parent questionnaires. Differences were found in intellectual function, visual-spatial skill, fine motor dexterity and particularly language-related skills, including vocabulary, word reading and applied math problem solving. Despite these group differences, outcomes were within the average range for most boys with ICH. No group differences were found in behavioural and socio-emotional functioning. Although ICH in haemophilia is not benign, it was not associated with significant cognitive and academic consequences for most boys. Early neuropsychological assessment may be indicated when there is a history of ICH. Investigation of age at ICH and quantitative measures of brain in relation to neurocognitive outcomes in larger groups of boys with ICH would be useful.

Dopamine antagonist alters serum cortisol and prolactin secretion in lactating Holstein cows.

The role of dopamine in regulating glucocorticoid and prolactin secretion was investigated in lactating Holstein cows by characterizing serum cortisol and prolactin responses to fluphenazine, a dopamine receptor antagonist. Twelve anovulatory cows received an intravenous bolus injection of either saline (n = 6) or 0.3 mg of fluphenazine/kg of body weight (n = 6) in wk 2 postpartum. Blood samples were collected every 30 min for 4 h before and 4 h after saline or fluphenazine injection. Serum progesterone concentration was 0.13 +/- 0.1 ng/mL and did not differ between groups. No difference in serum cortisol concentrations was detected between groups before treatments. Fluphenazine increased serum cortisol concentrations within 30 min after fluphenazine administration (>30 ng/mL) and concentrations remained elevated throughout the sampling period. Cortisol remained unchanged in saline-treated cows (<10 ng/mL). Prolactin concentrations also increased after fluphenazine administration (103.1 +/- 3.1 ng/mL), but were unaffected by saline (18 +/- 3.1 ng/mL). Prolactin concentrations remained elevated throughout the sampling period in fluphenazine-treated cows. Our results indicated that a dopamine antagonist increased cortisol, suggesting that endogenous dopamine, at least in part, regulates cortisol and prolactin secretion. These effects are regulated through dopamine receptors in anovulatory lactating dairy cows during the early postpartum period.

Comprehension skill, inference-making ability, and their relation to knowledge.

In this study we investigated the relation between young children's comprehension skill and inference-making ability using a procedure that controlled individual differences in general knowledge (Barnes & Dennis, 1998; Barnes, Dennis, & Haefele-Kalvaitis, 1996). A multiepisode story was read to the children, and their ability to make two types of inference was assessed: coherence inferences, which were essential for adequate comprehension of the text, and elaborative inferences, which enhanced the text representation but which were not crucial to understanding. There was a strong relation between comprehension skill and inference-making ability even when knowledge was equally available to all participants. Subsidiary analyses of the source of inference failures revealed different underlying sources of difficulty for good and poor comprehenders.

Comparison of literal, inferential, and intentional text comprehension in children with mild or severe closed head injury.

BACKGROUND: Children with head injury have impairments in pragmatic language at the level of both single words and texts. Text comprehension deficits are likely to be the more consequential for everyday and academic function, yet the relative magnitudes of literal and nonliteral text comprehension deficits have not been measured. DESIGN: We compared the magnitude of the impairment in three forms of text comprehension for children with mild or severe head injury relative with controls: literal language (understanding literal text information), inferential language (making pragmatic inferences, textual coherence inferences, or enriching inferences), and the language of mental states and intentions (eg, producing speech acts, appreciating irony, and understanding deception). MEASURES: Effect sizes were used to measure the magnitude of the difference between children with head injury and age-matched controls. RESULTS: Children with severe closed-head injury were significantly impaired on tasks of literal text understanding, inferencing, and intentionality. Children with mild head injury were impaired on some inferencing and all intentionality tasks, although they had no literal text comprehension deficits. CONCLUSIONS: For both groups, the greatest deficits (ie, the largest effect sizes) were on tasks requiring understanding of the language of mental states and intentions. The data bear on the long-term effects of childhood closed-head injury on text- and discourse-level language and also on the nature and timing of language rehabilitation in children with head injury.

Children with spina bifida perceive visual illusions but not multistable figures.

We compared 32 children with spina bifida and 32 age-matched controls on two classes of illusory perception, one involving visual illusions and the other, multistable figures. Children with spina bifida were as adept as age peers in the perception of visual illusions concerned with size, length, and area, but were impaired in the perception of multistable figures that involved figure-ground reversals, illusory contours, perspective reversing, and paradoxical figures. That children with spina bifida reliably perceive illusions that rely on inappropriate constancy scaling of size, length, and area suggests that their brain dysmorphologies do not prevent the acquisition of basic perceptual operations that enhance the local coherence of object perception. That they do not perceive multistable figures suggests that their visual perception impairments may involve not object processing so much as poor top-down control from higher association areas to representations in the visual cortex.

Understanding of literal truth, ironic criticism, and deceptive praise following childhood head injury.

Children with closed head injury (CHI) have semantic-pragmatic language problems that include difficulty in understanding and producing both literal and nonliteral statements. For example, they are relatively insensitive to some of the social messages in nonstandard communication as well as to words that code distinctions among mental states. This suggests that they may have difficulty with comprehension tasks involving first- and second-order intentionality, such as those involved in understanding irony and deception. We studied how 6- to 15-year-old children, typically developing or with CHI, interpret scenarios involving literal truth, ironic criticism, and deceptive praise. Children with severe CHI had overall poorer mastery of the task. Even mild CHI impaired the ability to understand the intentionality underlying deceptive praise. CHI, especially biologically significant CHI, appears to place children at risk for failure to understand language as externalized thought.

Knowledge-based inferencing after childhood head injury.

Inferencing was studied with a story comprehension task that required inferences to be made from a controlled knowledge base. Despite similar rates of knowledge base acquisition, knowledge base retention, and speeded access to the knowledge base across groups, the 18 children with severe head injury had lower rates of inferencing than the 15 children with mild head injury or the 18 age-matched controls. Results suggest that cognitive functions such as working memory and metacognitive skill that are disrupted by severe head injury may also play a role in some of the text- and discourse-level deficits commonly reported in these children, notably those involving inferencing.

Poor reading comprehension despite fast word decoding in children with hydrocephalus.

Children with hydrocephalus decode words better than they understand what they read. We tested whether children with hydrocephalus (from myelomeningocele or aqueduct stenosis) (1) decode words slowly, (2) use decoding processes similar to those of neurologically intact peers, and (3) comprehend poorly to the extent that they are slow decoders. We compared speed of word decoding in 33 children with hydrocephalus and 33 controls matched on a pairwise basis for age, grade, and word decoding accuracy. The children with hydrocephalus were as fast as controls in reading words, but, unlike controls, they did not demonstrate an effect of spelling-sound regularity. Further, decoding speed did not contribute to reading comprehension beyond word decoding accuracy. The reading comprehension deficits of good decoders with hydrocephalus are not related to early-stage processing deficits in word recognition speed. Likely origins of comprehension failure in this group are discussed.

Effect of naloxone on serum luteinizing hormone concentration in anovulatory Holstein cows during the early postpartum period.

This experiment was conducted to investigate the effect of naloxone (NAL), an opioid receptor antagonist, on pituitary LH secretion in anovulatory Holstein cows during the early postpartum period when cows were expected to be in negative net energy balance. Twenty-three cows (11 primiparous) received either saline (n = 12) or 1 mg/kg BW NAL i.v. (n = 11) on Day 14 or 15 postpartum. Jugular blood samples were collected at 15-min intervals for 2 hr before and 2.5 hr after NAL or saline. All cows received 3 ug gonadotropin releasing hormone (GnRH) at 2.5 hr post-NAL or -saline and blood collection was continued for 1 hr. Mean serum progesterone concentration was 0.33 +/- 0.2 ng/ml. Mean net energy balance for all cows was -5.5 +/- 0.6 Mcal/day. Naloxone caused a transient increase (P < 0.05) in serum LH concentrations in both primi- and multiparous cows within 45 min after administration. In contrast, serum LH concentrations remained unchanged in saline-treated cows. GnRH increased (P < 0.05) LH and there was no effect of treatment. These results suggest that modulation of LH secretion, at least in part, may be mediated via endogenous opioids in dairy cows before first postpartum ovulation.

Discourse after early-onset hydrocephalus: core deficits in children of average intelligence.

A review of our studies of oral and written language in children with early-onset hydrocephalus suggests that hydrocephalus is associated with specific deficits in discourse as opposed to generalized linguistic deficit. It is proposed that the language skills that are impaired in hydrocephalus are those that require context to derive meaning, while those that are intact may function relatively independent of particular discourse contexts. This hypothesis was tested in two discourse studies comparing children with hydrocephalus of average verbal IQ to age-matched controls. Study 1 investigated narrative economy, syntactic complexity, and semantic content in the retellings of familiar and less familiar fairy tales. Despite producing quantities of story content similar to controls and using syntactic economy similar to controls, the hydrocephalus group produced less of the core semantic content of both familiar and less familiar tales. Study 2 investigated inferencing and figurative language understanding in a narrative comprehension task. Even when prior knowledge was controlled, the hydrocephalus group had difficulty making inferences and recalling factual information from the story. In contrast to their ability to understand idiomatic figurative expressions, the hydrocephalus group had difficulty interpreting novel figurative expressions. The results are compatible with the hypothesis that the core discourse deficits characteristic of children with hydrocephalus are concerned with computing meaning from context. Putative processing features underlying the proposed core discourse deficit are discussed.

How children with head injury represent real and deceptive emotion in short narratives.

Narratives are not only about events, but also about the emotions those events elicit. Understanding a narrative involves not just the affective valence of implied emotional states, but the formation of an explicit mental representation of those states. In turn, this representation provides a mechanism that particularizes emotion and modulates its display, which then allows emotional expression to be modified according to particular contexts. This includes understanding that a character may feel an emotion but inhibit its display or even express a deceptive emotion. We studied how 59 school-aged children with head injury and 87 normally-developing age-matched controls understand real and deceptive emotions in brief narratives. Children with head injury showed less sensitivity than controls to how emotions are expressed in narratives. While they understood the real emotions in the text, and could recall what provoked the emotion and the reason for concealing it, they were less able than controls to identify deceptive emotions. Within the head injury group, factors such as an earlier age at head injury and frontal lobe contusions were associated with poor understanding of deceptive emotions. The results are discussed in terms of the distinction between emotions as felt and emotions as a cognitive framework for understanding other people's actions and mental states. We conclude that children with head injury understand emotional communication, the spontaneous externalization of real affect, but not emotive communication, the conscious, strategic modification of affective signals to influence others through deceptive facial expressions.

Misleading results from immunoassays of serum free thyroxine in the presence of rheumatoid factor.

A novel interference with measurements of serum free thyroxine (FT4) caused by rheumatoid factor (RhF) is described. We found misleading, sometimes gross, increases of FT4 results in 5 clinically euthyroid elderly female patients with high RhF concentrations. All 5 patients had high FT4 on Abbott AxSYM or IMx analyzers. "NETRIA" immunoassays gave misleading results in 4 of the 5 patients; Amerlex-MAB in 2 of 4 patients; AutoDELFIA in 2 of the 5; and Corning ACS-180 and Bayer Diagnostics Immuno 1 in 1 of the 5. BM-ES700 system results for FT4 in these women remained within the reference range. Results for serum T4, thyroid-stimulating hormone, free triiodothyronine, thyroid-hormone-binding globulin, and FT4 measured by equilibrium dialysis were normal in all 5 patients. Drugs, albumin-binding variants, and anti-thyroid-hormone antibodies were excluded as interferences. Addition to normal serum of the RhF isolated from each of the 5 patients increased the apparent FT4 (Abbott AxSYM). Screening of 83 unselected patients demonstrated a highly significant positive correlation between FT4 (Abbott AxSYM) and RhF concentrations. Discrepant, apparently increased FT4 with a normal result for thyroid-stimulating hormone should lead to measurement of the patient's RhF concentration.

Effects of anisosmotic stress on cardiac muscle cell length, diameter, area, and sarcomere length.

The purpose of this study was to examine the effects of anisosmotic stress on adult mammalian cardiac muscle cell (cardiocyte) size. Cardiocyte size and sarcomere length were measured in cardiocytes isolated from 10 normal rats and 10 normal cats. Superfusate osmolarity was decreased from 300 +/- 6 to 130 +/- 5 mosM and increased to 630 +/- 8 mosM. Cardiocyte size and sarcomere length increased progressively when osmolarity was decreased, and there were no significant differences between cat and rat cardiocytes with respect to percent change in cardiocyte area or diameter; however, there were significant differences in cardiocyte length (2.8 +/- 0.3% in cat vs. 6.1 +/- 0.3% in rat, P < 0.05) and sarcomere length (3.3 +/- 0.3% in cat vs. 6.1 +/- 0.3% in rat, P < 0.05). To determine whether these species-dependent differences in length were related to diastolic interaction of the contractile elements or differences in relative passive stiffness, cardiocytes were subjected to the osmolarity gradient 1) during treatment with 7 mM 2,3-butanedione monoxime (BDM), which inhibits cross-bridge interaction, or 2) after pretreatment with 1 mM ethylene glycol-bis(beta-aminoethyl ether)-N, N,N',N'-tetraacetic acid (EGTA), a bivalent Ca2+ chelator. Treatment with EGTA or BDM abolished the differences between cat and rat cardiocytes. Species-dependent differences therefore appeared to be related to the degree of diastolic cross-bridge association and not differences in relative passive stiffness. In conclusion, the osmolarity vs. cell size relation is useful in assessing the cardiocyte response to anisosmotic stress and may in future studies be useful in assessing changes in relative passive cardiocyte stiffness produced by pathological processes.

The effects of knowledge availability and knowledge accessibility on coherence and elaborative inferencing in children from six to fifteen years of age.

Two experiments are presented in which a novel knowledge base was acquired by 6- to 15-year-old children prior to hearing a multiepisode story, and where inferences from the story drew only on that knowledge base. Making knowledge equally available to all children did not attenuate age-related differences in either coherence or elaborative inferencing. Easily accessible knowledge was generally twice as likely to be used to make inferences during text comprehension as was knowledge that took longer to retrieve, though knowledge accessibility was more important for coherence inferencing in younger than in older children. Children made more coherence than elaborative inferences in the context of text comprehension, even though elaborative inferencing was more frequent in a simpler processing situation. Within the context of an available knowledge base, the results provide evidence for the importance of knowledge accessibility in children's inferencing, and for the changing developmental relevance of knowledge accessibility for coherence and elaborative inferencing.

Load effects on gene expression during cardiac hypertrophy.

Hemodynamic load is a primary regulator of cardiac mass. A potential proximal event in this regulatory pathway is thought to be the induction of immediate early genes, and markers of this process include the re-expression of genes for fetal sarcomeric proteins and the ventricular expression of atrial natriuretic factor (ANF). Previous in vivo models which have examined these questions have often neither quantified myocardial loading nor accounted for covariables which may affect gene expression such as the renin-angiotensin-aldosterone system, the sympathetic nervous system, or baroreceptors. Thus, whether load alone is sufficient to induce immediate early genes, which may ultimately result in cardiac hypertrophy, remains unknown. In the present study two models of right ventricular (RV) pressure overload were created by partially occluding the pulmonary artery (PA), either with a balloon catheter for 1 or 4 h, or with a surgically placed PA band for 12, 24, or 48 h. Serum catecholamine concentrations were determined in a subset of RV pressure overload cats at basal state, after 5 min of balloon inflation, and after 1 h of balloon inflation to examine the effects of this systemic trophic factor on IEG induction. Northern blot analysis for c-fos, egr-1, alpha-skeletal actin, and ANF from paired RV and left ventricular (LV) RNA allowed the effect of load (selectively increased in the RV) to be separated from other systemic variables (present in both ventricles). The relative signal intensities of the optical density of RV and LV mRNA autoradiograms were determined from northern blots, alternate lanes of which were loaded with 7.5 micrograms of total RNA from RV and LV tissue from the same cat. Partial PA occlusion caused RV systolic pressure to increase from a control value of 22 +/- 1 mmHg to 57 +/- 6 mmHg after 1 h, 59 +/- 5 mmHg after 4 h, and 58 +/- 5 mmHg after 48 h of RV pressure overload (RVPO). Serum norepinephrine and epinephrine levels at both 5 and 60 min of RVPO were not significantly different from basal levels. The RV/LV ratios of mRNA for both egr-1 and c-fos were equal in control and 48 h PA banded animals, but were increased in the 1 and 4 h balloon RVPO cats. The RV/LV ratio of mRNA for alpha-skeletal actin was equal in the basal state and did not increase after 12, 24, or 48 h of RVPO. After 48 h of RVPO, total RNA was increased in the RV compared with the LV (1.9 +/- 0.1 v 1.1 +/- 0.1 micrograms/g tissue, P < 0.05). ANF expression was present in the RV after 48 h of RVPO, but absent in same-animal LV and all control ventricles. Thus, while increased load alone did not alter the expression of alpha-skeletal actin, it was sufficient both to induce increased expression of two distinct classes of immediate early genes, as well as ANF, and to increase total RNA, indicating hypertrophic growth initiation.

Neuropsychologic function in same-sex twins discordant for perinatal brain damage.

We studied childhood neuropsychologic function in two pairs of low birth weight, same-sex twins reared together but with different patterns of concordance and discordance for intraventricular hemorrhage (IVH) and hydrocephalus (HYD). Same-sex twins have discordant levels of cognitive skills when one twin but not the other develops IVH alone or IVH and HYD at birth. The results bear on several issues: the effects of prematurity, the effects of IVH, the combined effects of IVH and HYD, and the potential applications of the present methodology of pairwise-matched twin comparisons for understanding how different forms of perinatal brain damage affect childhood cognitive functions important for learning.

The content of narrative discourse in children and adolescents after early-onset hydrocephalus and in normally developing age peers.

The development of narrative content was studied in 100 children aged 6-15 years (49 with early-onset hydrocephalus and 51 age-matched controls) by analyzing transcripts of oral texts produced from their narrations of two fairy tales. In relation to those of their age-matched peers, the narratives of the children with hydrocephalus were less cohesive and less coherent. They conveyed less of the content needed for the narrative message, included more referentially ambiguous material, included uninterpretable or implausible content, and were more verbose and less economic in quality. In relation to their age-matched peers, then, children with hydrocephalus produce narratives that are difficult to process, unclear, uneconomic, and less fully elaborated for meaning. These data add to an emerging body of information that shows children and adolescents with early-onset hydrocephalus to be at risk for several types of discourse and pragmatic impairments. The language of children with hydrocephalus is discussed with reference to the theoretical distinction between interpersonal pragmatic conventions and constraints relating to textual rhetoric (processability, clarity, economy, and expressivity). By showing impaired textual rhetoric coexisting with apparently preserved interpersonal rhetoric in individuals with developmental anomalies of brain development, the present data provide some support for a functional dissociation between the two classes of pragmatic constraints.

Oral discourse after early-onset hydrocephalus: linguistic ambiguity, figurative language, speech acts, and script-based inferences.

Studied 101 children, ages 6 to 15 years (50 with early-onset hydrocephalus, 51 normally developing), on four oral discourse tasks: establishing alternate meanings for ambiguous sentences; understanding figurative expressions; making bridging inferences; and producing speech acts. Children with hydrocephalus performed more poorly than controls on all four discourse tasks; and a higher-IQ hydrocephalus subgroup performed more poorly than controls on all but the figurative expressions task. The fluent, grammatically framed, but content-impoverished language described in early-onset hydrocephalus appears to reflect not so much problems in deriving word- and sentence-based meaning as deficits in the pragmatic use and understanding of language in discourse.

A synthetic opioid peptide increases plasma growth hormone and prolactin in Holstein calves.

The effect of the synthetic opioid agonist D-Ala2,N-Me-Phe4,Met(O)5-ol enkephalin (DAMME) on plasma growth hormone (GH) and prolactin (PRL) concentrations in Holstein heifer calves was investigated in this study. The possible site of action of DAMME was determined by pretreating calves with an opioid antagonist that crosses the blood-brain barrier poorly if at all (N-methyl levallorphan-methane sulphonate [MLM]) or one that crosses readily (naloxone [NAL]). All calves were assigned to one of three treatment groups: 1) pretreatment with saline, 2) pretreatment with NAL, or 3) pretreatment with MLM. All groups were injected with DAMME 30 min after pretreatments. Plasma PRL increased after injection of DAMME in calves pretreated with saline. Prolactin concentrations were not different before and after injection of DAMME in calves pretreated with either NAL or MLM. Plasma GH increased after injection of DAMME in saline- and MLM-pretreated calves but was unchanged in NAL-pretreated calves. These data show that peripherally administered DAMME increases plasma GH and PRL in Holstein heifer calves and suggest that DAMME mediates GH release through receptors located somewhere inside the blood-brain barrier, but it can induce PRL secretion at a site located outside the barrier.